Unless you're playing games hosted internationally you shouldn't be getting a lot of lag. I take it you're gaming on an xbox? If you aren't playing locally hosted games, head over to the
local xbox forums and add some players to join local lobbies.
Mweb's Acceptable Usage Policy is one of the best out there. Are you currently being throttled? Can you post both local and international speedtest results?
If you want the "ultimate experience" I'd suggest staying with Mweb when upgrading to 10mb. That's if you're willing to pay the exorbitant monthly fee. Although 10mb is a bit overkill imho.