I have an Eclipse hood on a 37g
FOWLR tank. The only PRO is that it is one self-contained unit. You can throw away the bio wheel assuming you're using
lr.
There are tons of CONS, the biggest is limited lighting capacity. I put in a 65w retro kit (which I believe you can purchase from Champion Lighting or other sources), the issue with that is that the normal plastic enclosure around the lighting heats up big time with the 65W and actually will change shape due to the heat.
The other CON is adding additional equipment. You need to mod the top to suite your needs (mod = use a hacksaw). I purchased a Red Sea 60 protein skimmer that I was able to insert into the rear right square access point, but had to cut off part of the hood (on the inside, so nobody can see it) to fit it in. The nice thing is that with the cut it almost fits perfectly into this square. The skimmer requires cleaning, but seems to produce a good amount of brown gunk every day.
I basically use the built-in pump/filter in the hood just to circulate water, but once a month or so put in charcoal into some old Eclipse-style filters that I've ripped apart for a couple of days.
I've had my 37g with Eclipse for about a year and a half, and it has worked well, but it has presented limitations that I need to work around, biggest being lighting options. I'm not sure if I can do anything about 65w in this hood without melting the plastic (and there is no room that I can tell). I was just talking to my wife this morning about getting rid of the hood and making a new hood, or getting rid of the tank and moving up to a 75 or 90g.
Good luck..and
btw I read a lot of reviews on Eclipse hoods before jumping into a sw setup..we previously had fw in the Eclipse. I was initially going to dump the Eclipse, but for a
FOWLR tank it has worked with the minor mod mentioned above to fit the ps. It will work, you just need to know what your limitations will be.