Disclaimer
This comparison is my opinion only - please visit both areas and determine for yourself.
Background
I lived in Chattanooga for nearly 2 years and moved to the Upstate in 2008. In Chattanooga (for those local), I lived on Missionary Ridge and actually worked in NW Georgia (Trenton) - Chattanooga sits on the TN/GA state line. In the Upstate, I've lived in Simpsonville and now live within the Greenville city limits. I've worked in Gaffney, Spartanburg, and (now) Greer.
Commentary
I'm surprised that Chattanooga and Greenville are not compared more frequently. Both have similar paths - a history of dilapidated downtowns with significant revitalization beginning 15-20 years ago. Both areas have received national exposure with their downtown development. In fact, Chattanooga used to be one of the dirtiest cities in the country and is now one of the cleanest. I'm also surprised at how slow the Chattanooga sub-forum is compared to the Greenville sub-forum. I suppose that's due (in part) to all the "half-back" interest in North and South Carolina.
Chattanooga
(I will expound on Chattanooga much more so than Greenville)
Some are surprised, but this a very scenic city. Lookout and Signal mountains (2,000 feet+) immediately surround the city center (elevation about 680 feet). Chattanooga's CSA is about 650K (about half that of the Upstate). Chattanooga has easy access to Atlanta - about 1 and 1/2 hours Southeast - with 3 lanes of traffic spanning
the entire distance to Atlanta on I-75 (wonderful interstate). Additionally, one can get to Knoxville, Birmingham, and Nashville quite easily.
The economy of Chattanooga is not as robust as the Upstate. However, VW's US headquarters is now under construction there. Additionally, Krystal, Chattanooga Bakery ("Moon Pies"), Olan Mills, Unum, and Covenant Transport are headquartered there. Interestingly, Little Debbie (McKee Foods - privately held) is headquartered in Chattanooga as well (my wife tried to obtain a tour with a Mom's Group and was flat out told "no" due to their proprietary food techniques).
Utilities in both regions are equally inexpensive and reliable. Interestingly, the water supply in both areas is robust. I recall no restrictions in either areas during droughts of the last 5 years. Cable is another matter however. Chattanooga is one of the few, fortunate cities in the country with competing cable outlets. Comcast competes with
EPB - the local electric utility company - which also provides high speed internet (
fiber to the home) to nearly the entire Chattanooga area. Additionally, AT&T U-verse is also available.
Public education in Chattanooga is perhaps a step below the Greenville area. However, there are easily identifiable pockets of excellent public schools (Signal Mountain, maybe Ooltewah). Conversely, the private schools in the area are nationally renowned and outstanding (McCallie, Baylor, GPS). I do recall there are more private schools in Chattanooga per capita than anywhere in country.
Chattanooga has 3 main hospitals: Erlanger, Park Ridge, and Memorial. Erlanger is the only Level 1 Trauma Center in the area and offers numerous medical residencies - very comparable to GHS here.
Chattanooga is considered a tourist destination in the South. Attractions include:
Tennessee Aquarium (awesome),
Creative Discovery Museum (incredible children's museum),
Chattanooga Choo Choo,
Hunter Museum of Art,
Lookout Mountain Incline Railway (great),
Rock City, and Ruby Falls.
Much like Greenville, outdoor activities are plentiful in Chattanooga. Locally, Chattanooga has the absolutely incredible
Riverpark system - miles and miles of
paved walking and biking trails adjacent to the Tennessee River (that flows thru downtown Chattanooga). The
Ocoee River is less than hour east and offers fantastic rapids and sightseeing. Hang-gliding is very popular in the area (especially off Lookout Mountain).
Downtown Chattanooga is story of renaissance (much like Greenville). Downtown Chattanooga is at least 2-3x bigger than the downtown area of Greenville. Additionally, the Tennessee River (that flows thru downtown) is (of course) much larger than the Reedy River. Major attractions (as mentioned above), restaurants, and shops complement the walkable downtown area. Chattanooga has 7 bridges spanning the Tennessee River with most of them walkable with pedestrian lanes. Note that the
Walnut Street Bridge is the second longest pedestrian bridge in the
country.
Shopping/dining are perhaps a step below Greenville. Chattanooga does not have a Costco (one under construction though), Whole Foods, Ruth's Chris, Trader Joe's, Apple, Total Wine, IMAX (for first run movies), etc. Grocery shopping used to be dismal in Chattanooga prior to the introduction of Publix in 2007. Hamilton Place Mall is the largest indoor mall in TN - it's aesthetically much more appealing than Haywood Mall (Haywood's outside facade needs rehab badly) but does not have some of Haywood's upscale stores. The flagship GreenLife Grocery store on the North Shore (now acquired by Whole Foods) is incredible and I would argue is nicer than the Whole Foods in Greenville. Earth Fare is now in Chattanooga as of 2010. One note: TN state law does not allow wine to be sold in grocery stores - there, wine is more expensive than the Upstate. The new Costco being built lies just within the GA state confines and, of course, will allow wine sales.
Chattanooga does have
Lupi's which is the best pizza I've had anywhere in the South - that place is phenomenal (much better than any pizza place in Greenville). Additionally (prior to Papas and Beer opening), Greenville has had some very disappointing Mexican restaurants. I'm still shocked to hear that people still recommend Monterrey's by the Mall (in Greenville) - that place is awful. Chattanooga has mexican restaurant called
La Altena that is arguably one of the best restaurants in the city.
TN does have a
statewide tobacco ban - no smoking in restaurants or workplaces. I do not eat in any restaurants that allow smoking - therefore, I strongly prefer not to eat in Simpsonville, Greer, or Spartanburg. Fortunately, some mindful restaurant owners in the Upstate have banned smoking themselves (thank you Renato's in Spartanburg - that place is incredible).
Climate is nearly identical with winters being a touch colder in Chattanooga (lies on the west side of the Apps) but with much less ice than the Upstate (Greenville is on the east side of the Apps/Blue Ridge and subjected to
CAD/"Wedge").
An important note that TN does not have a state income tax and does not have a property tax on cars. Some TN counties/municipalities do have a "wheel tax" in place of property taxes that can be somewhat costly - Chattanooga (Hamilton County) does not. Interestingly, Chattanooga does require emissions testing but this is very cheap. I'm not quite sure why the Upstate does not require this. Also note that sales taxes in TN are quite high on
everything - 9.5% in Chattanooga as I recall.
Greenville
I'm going to keep this brief - there are other wonderful posters here.
Overall, Greenville is wonderful place for retirees and families and offers a multitude of activities, very good shopping, easy to manage traffic, and low cost of living.
Some random noticeable differences with Chattanooga:
Greenville proper is not nearly as scenic as Chattanooga but access to higher elevations (and mountains of Western NC) is much easier. I also appreciate the easy access to Asheville (1 hour drive). Additionally, I've never seen a concentration of so many waterfalls in any other part of the country. There are dozens of
waterfalls near/on the Blue Ridge Escarpment.
There is a state tax here and there are annual property taxes on autos. I'm nearly certain tax on (unprepared) food is 0%. Tax on new car purchases is only $300. Gasoline taxes are dirt cheap.