Depends on your budget for the polisher,you can buy a cheap silverline which is a copy of the makita for around £60,or you can buy a flex which is regarded as one of the best machines for about £400.
Ive got a flex and a das pro DA polisher,as far as polish goes theres loads out there 3M, menzerna,Meguires,Scholl ect
Best place to go for advice is www.detailingworld.co.uk