There are lots of systems out there I would say the most popular are Lenz, NCE, and Gaugemaster. No matter who you ask they will always say there's is the best. Just remember if you ask in a shop they will most likely tell you what they sell is the best (remember they just want your money) Your best bet is to talk to a dealer who specialise in DCC. The like of DCC Supplies sell lots of systems and will give you plenty of advice. I use NCE myself.