The best quality, IMO, is Arbo, if budget isn't a problem. Best value for money I've seen is probably Everbuild.
Just did a strip an polish with the Amtico dressing and come up great. Could be anything in that though
I would always suggest something fairly matt so as not to enhance the plastic nature of the floor. The Amtico products AFAIK are rebranded Johnsons products and are of good quality. Dr.Schutz PU Sealer is the ultimate in protection. However it does come with a (justifiable) price ticket. Dr.Schutz also have their Medica and Secura sealers which shouldn't be overlooked either as they the toughest of the non-PU sealers I have come across.