If southern digital is still around they had good prices too...
In this case, you are buying a commodity, if you have a problem, warranty is covered by NCE no matter who you buy it from (as long as it is new).
So, as long as it is delivered, I would not worry who I bought it from.
None of the places that sell it are going to support you in programming or learning DCC, you have to learn that on your own pretty much (and that is the best way)
p.s. I stopped buying from the cheapest dealer long ago, Reindeer Pass and RLD Hobbies are my vendors of choice.