Is it the new style hood or the old one (both are A series, old one is Tier 2, new is Tier 3).  We demoed an RT120A in 2007... and liked it so much that we bought a MF 7485 (equivalent to an RT 135).  Apart from colour they are the same (and the MF is a Tier 3).  Engine is absolutely great!  Quietest engine you will find, very lively, uses very little fuel.  This spring I hauled manure during something like 25 hours before needing to refill (and I was incorportating the manure with the spreader).  Cab is great and quiet.  Maybe not as large as its green or red counterparts, but still good.  Only way to make it better would be cab suspension (which we should have ordered).  Transmission is another plus... rear axle and transmission comes from Fendt (if it is a CVT).  Works great, easy to use.  We usually road along at 25 mph, engine at 1700 rpm, with a 20 tonnes + load of manure.  

In conclusion, I would buy another one tomorrow morning if I was on the market for a new tractor.  Everything is great with those tractors. Cab could be improved, but I suits my needs.  Let me know if you have specific questions.

 Nick