hmm... i personally think the pills are more convenient but thats preference.
The quality difference well theres no difference atall except brand quality.
The shakes that contain powder are ok but the more content of the shake the more chance of the creatine being diluted and less effective so i'd recommend having a seperate protein shake and then take your creatine tabs (if you have protein shakes)...
Which brand is the best, well theres thousands of companies out there and i dunno where you live so... Name some products you wanna buy and i'll have a look as will other members i'm sure...
Avoid MuscleTech, Xyience.... from my own experience