Last weekend I had a full day with the Bobcat 337..thanks to the CT dealer which I have found thus far to be excellent. This is a significant jump in stability and capability over the 331. This excavator pulled out a buried boulder that the 331 could not. I could hold a larger rock with the arm extended perpendicular to the tracks without a hint of tipping. The last test was the strength in digging and pulling out a double tree trunk root ball that was nestled against a stone wall. The 337 got this out within 45 minutes. The size of the ball was 5' x 4' x 3' with soil. All of the controls and cab ergonomics are the same on the 337 when compared to the 331. In operation the 331 seemed smoother in moving the arm and bucket...is this because it had ~300 hrs compared to a new 337? Also at low rpms the 337 bogged down and stalled in traveling with slight turns. This was not a problem when slightly raising the rpms(~1200 rpm). Overall I found the 337 a better excavator for performing medium weight tasks(digging and lifting stones, stumps, etc.) on uneven ground. My impression was that the 331 was smoother to operate and would perform many digging tasks on flat surfaces. The terrain aspect to me was related to track width, track contact length, and excavator weight. During this test I started comparing the specifications, on paper, for several different 7.5K and 12K lb compact excavators and found significant differences. I will continue the comparisons in the next month with both Takeuchi and Yanmar excavators from the same weight categories. I will probably add the CAT excavators to the mix as many posters have added positive feedback. It appears that equipment leasing companies tend to steer towards certain brands and models is that for reliability reasons or fleet pricing?