I find I like the balance of my 5.5", but I also shove my hand about as high on the grip as I can. So it doesn't seem too topheavy to me.
I also don't see the point of having a threaded barrel if you don't use it. If you like the length or just the option, that's great. Personally, I'd have to put a compensator on it to feel right, to me.
If you want to suppress it, grab whichever you want. You can always have the 5.5" threaded for a pittance of what the actual suppressor would cost, anyway.