I currently have an xp2 and an xp3 on my 125g fw
, I've ran the xp1 but never the xp4 (wasn't out yet when I was buying filters)
The Rena Filstar XP models are winners in every aspect. low Maintenance, no leaks, and they are easily maintained with a no-leak quick disconnect from the hoses.
I'd recommend them to any enthusiest.