Absolutely this. It looks great, and the ability to use TAGinn with some mods is a nice selling-point... but ultimately it is an oversized overweight M203 (IIRC it's 4.1 kg w/o the scope rail), and that's not even considering the cumbersome and lengthy reload time (Venturi lock, open hinged breech, remove shell, unscrew shell end cap, replace grenade in the shell, reinstall shell end cap, rotate end cap to firing position, insert shell into breech, close hinged breech, action Venturi lock ?)
There is an undeniable coolness factor though, and the giant Titan cartridge looks great and holds a lot of gas, but at ~£120 for a shell + cartridge, additional "big" ammo is pricey