That really depends on a lot of variables, mostly which one you like the best.
If you have a brand new boat then the factory option is your best best as more and more manufactures void the hull warranty if you use a non-factory tower.
If price is no object get one custom made or just pick the one you like the most. All of the major tower companies build very nice products. There are a few real dogs out there but you rarely hear about them on these boards and you'd have to be digging real deep to find them.
Do a search at this and other boards. Check out http://www.worldwakeboardcouncil.com/links.html
for a list of all the major tower companies.
All of us that make towers would naturally believe ours to be the best and that all other towers will cause global warming and other terrible worldwide disasters