Yes, I usually use M too. 10-15 mph is plenty fast for me off road. I let off and get the "umph". Starting out, sometimes there is no alternative to L. Running, M is fine. That's not really a problem for me, just the shifting, and its not too bad. Dealer says he can fix though. He wants to wait for 50 hrs run time. Its under warranty so I'll let him give it a shot.
You might be pleasantly surprised after you get some hours and use on it. I was probably one of the very first people on here to buy a Kubota RTV900 and I know I was the first to post about the shifting problem. At first Kubota ticked me off and tried to blame it on me or tell me that it was "normal" to have to shut the engine off to change gear ranges if you stopped on a hill. After thousands of additional complaints, Kubota finally started to make changes.
Anyway, rather than wearing out or getting sloppy loose, my RTV900 picked up considerable engine power and the shifting issues all but went away after I worked the dickens out of mine by hauling several hundred 2000 pound plus loads and dumping them when I was filling in dirt next to my 1/4 mile concrete driveway. I posted a pic on here of my young son waiving from the RTV with a load of wet clay soil stacked in the bed higher than the roll cage.
My thought was that I would take a beating on selling the RTV900 so soon after they came out and the shifting issue becoming widely known. So, I figured I'd just work it into the ground and get some of my money's worth out of it. Imagine my surprise when it dumped every single load (way, way over it's rated limit), broke nothing, and became rather peppy (compared to how it was) and began to shift easily every time! So, rather than unload a "junk" machine from Kubota, I traded it on an RTV1100 because I wanted the cab comforts.
The only issue with the RTV1100 was, even with a larger engine, the additional weight made it seem sluggish compared to the RTV900 I had just traded. After a year's use it too ran a bit better, but not enough. Shifting was never a problem, but I absolutely despised it's sudden stop. So, after it was out of warranty, I added an aftermarket 'coast valve' (best single change I ever made) and added a turbo to fix the power issue. It's now been over a year since I added the turbo and coast valve and everything works just fine and nothing has broken. I'm not really impressed with the high air intake quality and it's rattling noise, but I can clearly see where it saves the air cleaner from a lot of dirt.
Now I just hop in mine and put it in "H" unless I'm going to be towing something or doing some relatively serious off-roading. The turbo didn't give me any additional speed, but I can now spin both rear tires taking off on concrete in "L". It's a far cry from what it once was! Good luck with yours. I'd bet you will get many years of trouble free service out of it.
