Here are a couple I was looking at if I ever upgrade. From the reviews I have seen they look great. Hopefully more people will chime in and help you out.
I recently just upgraded from a modded ASM G2 to a Octo Extreme 200 w/PPW and it is worth the money. It was a few dollars over $300 because of the extra pinwheel.
Those are all great skimmer choices. For under 300 bucks your best bet is the msx 200. THe vertex in 180 Would be a good choice too. It doesnt pull quite the air the sicce pump does but it is a little more user friendly as the pump is not directional like a stock sicce.
THe MRC ocean force is a nice unit but to get the larger size you would need you would go over budget.
Mojo~
I have the Aqua Euro USA 135 and love it for $200 it was the best move I have made in awhile....If the bigger model is anything like the 135 you will like it....I pull a full cup every other day close to everyday but I await till it is full. It is some of the rankest stuff I have smelled coming from a skimmer.....The only down fall is I would rather have a gate valve then the water level being a pull up or push down tube and the pump is not the best but I have read they have upgraded the pumps to a more efficient one.