As far as pumps I use a Mag drive and have never had any problems with it. RO
Im using a Kent Maxxima but as long as the system can produce RO
I dont think there is much of a difference in products except for price and how many GPD it can produce. and as far as a sump (I know i'll be criticized for this one) but I use an aquaclear 150 which has the bio balls taken out and live rock rubble added. Many will tell you to save money you can make a DIY
Sump from a 20 gallon tank instead of buying a $200 wet/dry which I pretty much turned into a sump and I would have to agree with all of them.