Use Drew at Heavy Metal Armory. Drew is uber 10-8.
Charlie @ University screwed me on a UZI deal afew years ago by selling me a gun he showed me in "stock" to get my cash upfront, but in reality didnt have any on Form 3 to actually transfer as he was waiting for them. Then he lied for months to cover it up.
More recently, Robert at Florida Firearms has proven to me he has no clue about NFA transfer protocol and courtesy. Paid cash in full for an MP5 suppressor, a week later dude is still giving me printer toner excuses (that he given me earlier in the week) as to why he cant take the 15 minutes fill out my Form 4. Helloooo WTF ? He looked at me like I was out of mind when I told him to refund my money.
Drew, although a drive to Bradenton, does your forms while you wait and hands them to you so you can mail them yourself and know they are on their way to the system. He did 1/2 and 1/2 instead of all up front for me too. That guy is squared away.
SRT in St Pete is good too if you can get directly to John Weir, the owner, instead of the hired help.