whats the best type and are they reliable...what are the pros and cons

Either u2u raptor700 on here or have a nosey through his posts (there isn't loads). He has full hand controls.including push button shift on both his Indy and his quad so knows them very well and gives them the thumbs up, says it's lightning quick.

i had a kliktronic system on my last mnr (R1) with push buttons on steering wheel. it was very very fast and totally reliable in my time with the car

Also flatshifter do an electric gear shift kit
flatshifter.com
graz

I have a full kliktronic setup available complete with titanium paddles, boss and steering wheel.