In the fall I went from a 10" Morbark to 15" bandit. I too have used Morbark for a lot of years, but the demos I did proved the bandits are better at munching. I did try a m15r with 170+\- HP Perkins and was amazed with the power and ability but it weighed 9700# as it was and I was capping myself at 7500-8000 because of my truck. The 1390xp I bought has the 130 hp GM and I have been happy so far (107 hrs). The only time I feel it's short on power is sending upwards of 12" of hardwood (osage, maple, oak) or when the knives get dull. I feel that over compensating on hp allows you to neglect the necessary maintenance (ie knives & anvil) because the extra power just pushed through (that's what my old boss used to do).
A word of caution with the Morbark, be careful with the RX models. The m15rx saves weight but only has 2 knives. The salesman tried to convince me it was better than the 4 knives... Don't let them fool you 4 is better! But all you gotta do is demo them and you will see. Good luck!!![/QUOTE
Just FYI The 165hp GM gas on the 15" machines is amazing. 2 knives work great, 4 knives work great too, lag and recovery times with equal HP will be different. More lag and recovery time with 2 knives at same HP and capacity, but both work great depending on your expectations and needs, those factors should play a part in how the machine should be outfitted. Also note we will have a 250+HP GM Gas option later this year for the 18" machines.