Of course. Although personally I would prefer APF/CSF as they provide more comprehensive options/use of droplists etc and can be managed via SSH.
I'm not a fan of Virtuozzo or it's tools to be honest, although I do like OpenVZ.
I agree... The Virtuozzo firewall is alright, but it only supports basic port blocking. This is fine for a "newbie" but any power user would prefer to run a full featured firewall in their VPS with more control.