If it were me, and cost would be an issue, I'd go with an AC 110 and a Rena xP3. Gotta agree that the xP4 isn't worth the extra money and has a lot more leaking/breaking down complaints. I haven't tried the aquatops or cascades and hear good things, except they don't last that long. If money isn't the issue, go Eheim, they last decades.
My FX5 was a piece of junk. I know a lot of people love them, but I just can't recommend.
On my 135 I use a homemade (really simple, all plastic) sump with 2 tower wet/dry's made out of stacked plastic containers and a soldering iron. And for mechanical a water bottle filter. I've seen no change since replacing the FX5 with the water bottle filter. Here's the site I took the basic ideas from (though I altered them)
http://dramaticaquascapes.com/doityourself.html
make sure to check page two for the wet/dry and overflows. These are cheap and really easy designs (otherwise I couldn't use them).
My FX5 was a piece of junk. I know a lot of people love them, but I just can't recommend.
On my 135 I use a homemade (really simple, all plastic) sump with 2 tower wet/dry's made out of stacked plastic containers and a soldering iron. And for mechanical a water bottle filter. I've seen no change since replacing the FX5 with the water bottle filter. Here's the site I took the basic ideas from (though I altered them)
http://dramaticaquascapes.com/doityourself.html
make sure to check page two for the wet/dry and overflows. These are cheap and really easy designs (otherwise I couldn't use them).