What is the difference between "Thumb type shifter" and "Rotator shifter"? Which one is good to use?? MTB/CYCLING.?

A "thumb" or "finger" shifter is one that you shift with your thumb or finger. A "rotating" shifter is one you use by rotating it. People call the rotating shifter "motorcycle style" because you "twist" in. It is circular and fits around your handlebar and you just twist it like you would a motorcycle throttle.

Which one is better depends on your personal taste and preferences. I have two bikes - one with the finger shift and one with the twist shift. The twist shift seems cool and easy to use and I prefer it for cross country style riding. I prefer the finger shift for downhill riding because, although I have to have a finger off of the handlebar and on the shifter, I don't have to move my hand/wrist in what may be a compromising position, to shift. It's not "awful" having the twist shift for downhilling... not really that much of a compromise... just seems a little safer - more control - with the finger shift.

A thumb shifter is a short, stubby shifter (usually) mounted on top of the bar, just inside the grip. Mostly worked with your thumb.

A twist shifter is a barrel that sits inside the grip, often replacing the inner 1/3 of it. You turn it like a motorcycle or an outboard motor throttle to shift.

I like twist shifters for winter use, as they can easily be shifted even with thick mittens on.

One downside is that they make the inner part of the grip thicker, which can interfere with comfort. Some people don't like the way shifting changes the angle of your hand on the bar.

Thumb shifters tend to be very robust and simple. Some even have a "friction" setting, making them compatible with a wide range of drive train options.

They're not the fastest way of shifting though.

Are you referring to the really old school thumb index shifters or the newer quick-fire trigger shifters? Only discount store bikes might still use those old style thumb shifters. JUNK.

Same thing with twist grip shifters. If you see a bike with either Shimano or SRAM twist grip shifters, run away. They're both junk found on low end bikes.

Here's what a lot of the better bikes are using today.

http://www.jensonusa.com/Shimano-SL-M4000-ShiftBra...