Get it on there, it's great. I would not be without ML on my 50D. There are not many ISO improvements, that is not really possible. It does offer DualISO which will expand the DR by up to three stops. That can be very useful if you are shooting subjects where you need to maintain detail in both the shadows and highlights. I use it quite a bit for backlit aviation subjects, where I want details on both the top and bottom side of the aircraft, and also the sky.
The other thing that I really is being able to lock an exposure value in manual mode, and then be able to change the shutter speed or aperture and have the camera adjust the other so that the exposure remains constant. With aircraft you really want to keep the shutter speed slow for propellor driven aircraft. I usually stay at or below 1/160. While for jets you want as fast as possible. The EV lock allows you to make those changes quickly, without affecting the brightness of the exposure.
Oh and of course it allows you to record 1080P video at up to 30 fps. The only thing is you will need a separate audio recorder.
Alan