I agree that the LT15 is a great mill, but after sawing on both the Mizer 15 and the Lumbermate 2000 i chose the Lumbermate.
I really like the way you can bolt options on the LM as you need them. They have a great log turner package that will easily turn the biggest logs and is a real back saver!
The LM will do everything it's advertised to do, and cost less than a LT15.
I've sawn with both the 13hp and the 15hp, and i couldn't see any difference in how fast they sawed... The Honda is a simpler design, that doesn't need electric start or all that goes with it. The Honda rolls over and starts VERY easy, and is a proven design...
The only advantage to having a bigger motor is how fast it will saw in bigger logs. The higher hp motors do saw faster, but if your not useing your mill for your primary income source, the 13 is just fine...
Both Norwood and Woodmizer are great companys that stand behind there product... I believe the LM will have LESS spl. parts in it, should you need a bearing or ? in it years later...
I hope this helped you some,
Rob