We had a wizard initially but we found it pretty weak overall. He was doing ok vs minions but we had a few cases of AE hitting the party that turned out to be pretty bad overall.
When he used flaming sphere at a start of a big fight he ruled that fight, but that was probably more having to do with the fact that if any lvl 1 daily is broken it's that one.
As soon as he started using at-wills mostly he sucked. Bad hit rate, low damage, slow that barely matters past round 1-2 of a combat, etc. Imo that's the sad truth of wizards.
Let's look at some numbers. Assuming a 20 int (60% hit rate) wizard with +1 damage bonus due to feat (either from staff focus or some other feat), you have the following dpr numbers for at-wills at lvl 1:
Magic Missile: 6.75.
Ray of frost = 5.8
Cloud of dagger with wisdom attack (14 wis) = 7.8
Scorching burst, assuming 2 targets which have to be pretty close and ideally in a position to not hit a friend with the spell: 11.65. And I want to stress the fact it's not trivial to always hit 2 good targets with the burst as far as I'm concerned. Monsters will want to melee you and get close to you.
Now let's look at the invoker: Avenging Light: 7.1 dpr off the bat, 8.9 dpr with the constitution bonus (16 consti, say a dwarf invoker).
Divine Bolts is basically a garanteed 2 targets which mean you are pretty much doing 11.65 dpr as long as you have 2 monsters within 10 range of you. This seem overall much better then scorching burst. Not counting the fact that Vanguard's Lightning is a direct upgrade and that the best controller spells they gave to controllers that I saw yet is Grasping Shards. I mean just better then ray of frost imo. Same range, same controlling effect but you get to clear the minions.
Playing an invoker tomorrow I would take grasping hands and probably divine bolts with a 20 wisdom built. As a human maybe I would add in avenging light with maybe 14 con or something similar. In those instances basically your at will are simply better then wizards and as for grasping hands it's probably better at control then even wizard's encounter at least for low level.
Just for comparaison as a striker you are looking at doing 12dpr or so with good builts minimum so doing 11.65 with divine bolts is nearly striker damage. I think wizards have decent encounters and good dailies (at least for doing damage, probably not for control though) at least early on but their at wills are very bad and since you rely on them a lot in the early levels that a major problem that the invoker doesn't seem to have (at least not as much).