In addition to the conc grenade, this guy has a flash bang grenade much like the Counter Strike grenade. You'll have to do some config work to get the zoom to work, and it's tricky to bind to the mouse wheel if that's what you are used to. As an added bonus, he gets the flash bang grenade, too. This is a very good class to get started with. The nail-grenade seems more powerful than the TFC version.
MIRV grenades have more sub-munitions and pipe jumping is very possible.
I love the smoke trails of the grenades as they are paid out of the launcher. One difference from TFC is that you only get 6 pipe bombs out at a time. You're going to have to spend some time with configs to get the detpacks to work as you like. Takes some getting used to with this big needle replacing the TFC Medic pack for healing and infecting. I have noticed that it isn't quite as obvious as TFC when you are infected, both for the infected and for teammates.