You may want to consider paying the extra three hundred (just $20 extra when divided by 15), as I understand from my husband that the front tine tiller just about beats you to death.....and that the rear tine works more smoothly. Yes, it would be an investment.....hopefully, everyone who used it would take care of it, and return it clean for the next part owner.
My husband loaned his out several times....and sometimes it would come back in less than clean condition....he wasn't too happy about that...and just stopped loaning it out. Hopefully, your group will have some kind of mutual agreement that it will be returned in a clean state...and anything broken will be repaired. If you test run it when it comes back....you'll know that it will be okay for the next person to use it.