I have to say that there are way too many issues with Match-making. Here are a few me and my friends have had problems with:
-Lag. I know the game just came out, but this game, at the moment is laggier than any other game I currently own, including Halo Reach and Battlefield 3, etc.
-Whoever the host is has a BIG, very noticeable advantage. Sometimes, I can literally lose a fight against an assault rifle while I'm using a SAW, point blank (and my bullets are connecting, even in the replay theater) Some shots get lost in the void and simply don't count as hitting my opponent. (A.K.A. This game has very poor hit detection)
-I'm tired of going full speed in my ghost and SMASHING into someone, and instead of them getting splattered, my ghost flips over them like they were made of stone and they shoot me in the face.
-The DMR is too powerful compared to other weapons. Since EVERYONE uses it, games become a long-range camp fest.
-Ordinances are ruining competitive play. They need to be toned down BIGTIME. It's so frustrating playing Slayer and you and your friends get Needlers and the other team gets a sniper and an incineration cannon, totally and senselessly turning the tides of the game.
-The Warthog does not have enough armor -- even with the Operator Specialization, they explode immediately because A.) there are too many power weapons being shot at it, especially lasers-- which are now a common weapon because of ordinances, or someone throws a couple plasma grenades on them (which everyone has because of the load out system) and the warthog blows to bits. Compare this to how hard it is to kill a tank or a Mech and it just doesn't make sense.
-Flood: On this gametype, if you are against the flood, you have to shoot them with your shotgun a good 3 seconds before they even swing or you both die even though you obviously shot them first.
-Instant Respawn makes no sense. A few times, I've killed someone and they re-spawned in range to shoot me with their DMR before I even had time to recharge my shield. I mean, really? :/
There are even more bugs/problems than that, but I won't go into them right now. I have visited the Halo Waypoint forums and I noticed that under the "Issues being investigated" thread, people have posted 200 PAGES full of complaints about the bugs in the infinity multiplayer.. It seems that there is absolutely no response on those forums from 343 industries, so they don't know where to turn for help. It's really disappointing and I hope these issues can be resolved. Thanks for reading.