Monks are melee only for one and I feel the have the stronger control effect in their flurry. They also have at will close bursts and lots of mobility. The monk is more durable in general and would have better defenses.

Sorcs can do it at range (though you can gish it up in melee but it is more dangerous) and can build a better nova. They also get access to the great arcane feat support (such as master riposte) and can more easily take advantage of energy vulnerabilities. Sorcs will also have better basic attacks in case you have a warlord around or some other class that grants you opportunity attacks. The more you attack the more the sorc comes out ahead. The sorc is more of a glass cannon but if you take the right utilities they can be very good at avoiding damage.