Price or usage?
ya I think so
All paintball guns are regulated at around 290 fps, the model is irrelevant.
The sierra one is the Canadian version of the Project salvo, which is the higher end version of the alpha black. If you want to save money for slightly better looks, get the alpha black.
The Canadian version of the alpha black is called the "bravo one" because the US one is sponsored by the US army. So, yes, they are legal to have in Canada.
They are cheap, durable starter markers. compared to most walmart guns, they are great. compared to mid level markers they are not.
No, you can not fit a double trigger in any of the US Army tippmanns.
Since the Diablo is almost a hundred dollars more, you will spend better money getting an e grip alpha black. Diablo does not have a reputation for well built markers.
The standard alpha black is semi auto mechanical. The egrip is electrically assisted with full auto and burst.
Real, as in holds paintballs, no. The magazine is a cleaning kit, you can store Allen Keys and O Rings inside of the Magazine, and when needed, the magazine can be removed.
The Alpha black does not come with a grip. If you want to attach a vertical grip, you need a rail attachment or ris shroud.