You can have the game search for games closer to your location.
Sometimes works out worse for us in the UK as it matches us up with French people, who always seem to get chosen as hosts, and always have a sucky connection.
I'm playing the 360 version, and yes, the hit detection is questionable (much like W@W), and the connection appears to be intermitent. It started off well, but over the past day or so it's been getting gradually worse, with constant 2 yellow bar connections. Tonight, we could get into games, but we never played the same lobby twice as it kept breaking them up.
Overall, quite happy with the SP campaign. Like MW2 it was fairly short, but, there was plenty of variety in the missions, and it was a decent (if predictable) story.
I strongly suspect that the true longevity of the game thought will be in the zombie mode. I'm glad I got the hardened edition as the classic maps are updated with sharper graphics, and the box spawns BO guns, and a few new mega-weapons (the thunder gun, and a freeze ray).
Dead Ops is great fun, on your own or with mates.
Training mode is great too if you just fancy having a blast without getting wrapped up online.
For me, MP is the weakest part. The maps are all fairly similar, and largely forgettable. The one exception is Cracked, which is a superb map. Beyond that, it's all traditional Treyarch problems; poor hit detection, weak guns, unbalanced weapons (lost count of the number of times I've put a clip into someone only for them to survive and kill me with a single shot from a pistol!), etc.
Is it better than MW2? In some ways yes, in other ways, no. Is it better than CoD4? Not a fucking chance.
I'd score this a 7/10 game.