In PvE maybe. In PvP it's complete shit. It's too predictable and easily blockable. If you rely on it a lot, you'll just get burnt.
Speaking of PvP, the Avelyn crossbow is hilarious in PvP when upgraded. It fires three fast bolts and is pretty powerful. The downside is that once you fire, you're open for a few seconds. Some people can predict it and block it too. But if you can surprise people with it, it's awesome.
It requires 25 Strength so it's nice for a Strength build. Str builds are awesome though. Powerful in PvE, and in PvP I can use Havel's greatshield for 45 strength with ridiculously good resists. Infuse that shit with magic, then laugh at mages. The Avelyn can be used to surprise mages too.
Mastodon Greatsword is a great strength weapon in PvP too. It scales A in Strength. The Halberd is powerful in PvE, but not so good in PvP.
Playing smart, I just tear people apart in PvP. Strength build is too good. I love the guard break action too.