I have a cheap filter that came with the tank but i know it won't be able to handle the Oscars so I'm buying a second filter. which one of these filters looks better?

www.aquariumguys.com/eheimecco1.html

www.aquariumguys.com/eheimcanister2.html

If you are limited to either one of those I would go with the one that has the highest gph flow rate.

Depends on the size of you tank. You want a flow rate of 4x the tank size for a cannister or 10x the tank size for an HOB. The two you are looking at:
2213 - 116gph
2233 - 145gph
If it's a supplemental filter in addition to the one you have, you need to factor in the flow rate of it as well. But, I would lean to the higher flow unit.

i can get any filter i just thought these two looked good for there price.

I just bought a canister filter for my tank, was relatively simple setup, some people don't like the magnum system since it has no bio spots in the filter. So far it is working great though and includes a vacuum attachment with the full kit. Not sure you can find another 350 GPH filter for this price range.

http://www.aquariumguys.com/magnumpro.html

Fluval or eheim trust me on this go for the expensive stuff so u only buy once and u cant afford filters to fail on u as filters are the heart of yr tank

Either get an Eheim or set up a mini reef (sump).. i think their the best ways to go. IMO.

Get the biggest and best filter you can afford!!!

I wish i had followed this advice when i started keeping fish. would of saved me a bundle of money

I have all fluval i have a 305 and a 405 on my o's tank,just got an fx5 to replace the 305.I want the 305 on another tank the fx5 is amazing!!Can't beat german quality.