cheaphydroponics.com has a spectra pure 90gpd for $179. It seems nice and works well. It doesnt have the canister or fixture, but heck I dont need em for this application. All I needed was a faucet adapter which I already had for my waterbed. If I owned my own home, I'd have gone for a bigger permanent system though.

With the walmart one, I'd just search the web for replacement filters to be sure they're readily available. Provided that, then it should be good.