The 2500 is a "slimmed down" version of the MH3000. When I bought the Meridian in 2006 with the MH3000, there was a similar rig parked next to it with the MH2500. At that time, the 2500 was a 5 speed trans, and the MH3000 was a six speed.
Since I owned the MH3000 first, and then went to the MH2500 the differences were immediately obvious. My 2500 did not shift as well as the 3000. When pulling a hill of any size the 2500 would "thunk" when down shifting. I could actually feel the coach shake when the shift occurred. The 6.7 ISB was strong enough, but when I crested the hill and backed off the throttle instead of the trans slipping back into the next higher gear, the trans would "hang up" in the current gear, say 2nd or 3rd for 5 to 15 seconds. Even without throttle input the trans hesitated to shift, and the RPM's would climb to over 3000+. When it did shift, it would slam into the next gear shaking the coach.
I had it looked at at several different Freightliner dealers, including Gaffney SC at the training center. Each time the diagnosis was that they could find nothing wrong, and that the trans was working "within specs". The Transynd fluid was checked and was at the correct level, and the filters were changed on schedule by Freightliner.
My personal opinion is that this trans was put forth by Freighliner to manufacturers as a cost saving measure over the cost of the MH3000. Part of the savings is that the MH2500 does not have "On Board Diagnostics" that is standard with the MH3000. The 2500 was installed in a 2010 Journey 34Y, which was 35' long. My loaded weight in the rig, which was "full time" loaded was 28,000# plus the weight of my Jeep which is 5,000#. Total going down the road was just over 33,000#, which was in spec for the rig.
I can not and will not condemn the trans in every application. However, I believe that at those weights it pushes the operating limits of that particular trans.
My current rig has the MH3000 behind a Cummins ISC 8.3 motor with 380 HP and 1050 Ft Lbs of torque. My rig alone is 37' long, and weighs 33,000# by itself, pulling the same Jeep for a total of 38,000#. The drive-ability is much better and all the shifting issues are gone.
So I would not tell someone to eliminate a particular rig because of the MH2500 trans. Just be aware of the issues and decide for yourself if the setup will work you.