I use penn plax's cascades in both my 55g and 120g, one 1500 in the 55 and two in the 120, they work very good, some critique them for having some "bypass" so not all the water that gets in goes throwgh the filter media, but I think the ammount is negligible, they have large media baskets, good and quite pumps, cleaning is easy, in short I do recommend them.
On the downsize they come with no bio media, only one sponge, some floss and one carbon bag, so you must add the cost of the bio media (anybody said sea-chem matrix?) to your total, so if you where looking at them just for the price you might get disapointed.
Other options you might want to look at are rena's xp3, xp4 or fluval's equivalent, and the very acclaimed but expensive eheim. I do still preffer penn plax because they work fine and I can get parts and support for them from my lfs, wich are two more things you need to consider before getting your filters.
Now back on topic wich CA/SA Cichlids, that size of a tank gives you some options, but the two fishes you mention limit them some how, imho I wouldn't put those in a 135g, as both will get very big, but that's just me, but thinking that you did, the bio load is already in the highs with them so you should have a very hard maintnace schedule if you placed many more fish in there, I would recommend maybe a green terror, because you need fish that is brave enough to get by the clown knife but not too brave to rip your aro.
If you don't put those two fishes then the options are very large to mention in this already large reply, but you could think a couple of oscars for example next to a large black knife and some silver dollars.
Maybe if you let us know more of your intentions, how aggressive you want your tank to be, how bad you want the aro and clown knife, and how often are you willing to do water changes you can get better answers in what to stock in your new tank.