as anything people will have varying opinions and i'm sure there are other comparable pumps, but i'll tell you why we went for these ones
1 - turnover rate - for that range of money you'll struggle to find anything decent with a higher turnover
2 - low running costs - compare the energy usage to a 'regular' powerhead and you'll be v surprised, helps keep the leccy bills down (big plus for us, we're closing half our tanks cos our leccy bills are coming in very very high at the moment)
3 - reliable brand
4 - they stick to the glass with magents not suckers meaning you haven't got to keep repositioning them when the suckers wear. in a big tank where i can't even reach the back where they are going to go without climbing on a stepladder and literally dunking my upper body into the tank that's a big plus!!