Umarex are just a licensing company, they don't manufacture the guns.
The Umarex 416 as far as I'm aware is made by VFC and is a gas blowback rifle, but if there is an AEG version, it will likely be around the same performance wise as the Top Tech.
The Top Tech 416 is made by G&G and is an AEG.
My personal experience with G&G is flawless, they are fantastic guns, I own 2 G&G rifles and they're the best guns I've ever had. On the other hand I have no experience with VFC, but I've heard nothing but good things.
I'd suggest waiting for a second opinion, or doing a bit more digging around. I'm sure either rifle will be perfectly fine and comparable in performance, though the VFC will have licensed trades since it's being distributed by Umarex.
