Best is a matter of opinion. It is a good choice for me I use them. Doesnt mean its the best choice for everyone.
Tell us a little about your tank.
I am currently using 2 hob emperor 400s on a 125 gal w 8 large S/a cichlids and have been told I need more filtration. I have the LFS trying to sell me Aquatop CF500UV 5-Stage Canister Filter with UV 9W, 525 gph do you know if these are any good?