i have looked at them all a lot reccomend the powertouch but this has a cam arrangement to engage i think the ego with its screw engagement is the best one unless you want to spend thousands on riech or truma
on our second powertouch, highly recommend them! Only issue is they tend to be rather slow but not a real issue. Five year warranty is very good though, we had an issue with the first one and they sent an engineer out within days to fix it no problem.