I generally use Litchfield station for my DCC needs, including fiddly bits like tweezers and wire and kapton tape and harnesses and well you get the idea.
I go with Tony's when I'm buying speakers, as I feel their "dream design" speakers do make a difference and sound better in the smaller sizes (which is what's needed to fit in an N scale anything). They also have an in between size like .63 inch (halfway between 1/2 and 3/4) which is a perfect fit for small HO Alcos I've been adding sound to for folks at the LHS. They also have a number of very useful loco specific decoders for HO engines, by far the majority of installs I do at the LHS, that are unique to them. They also have a bigger variety of odd goodies like the trainspeed (a scale mph/kph calculator/display).
When buying an expensive item or a bunch of similar items, I'll choose between Tony's and Litchfield solely by price as they both give excellent service.
Can't give a recommendation on DCC items from Chuck at FRTS, as I'm a Digitraxphobe and always buy NCE or TCS if I can so haven't bought anything in the way of DCC there. But I'm sure he'd provide the same excellent service as he has for any of the myriad of N scale goodies I've gotten from him over the years.