I try to avoid negative comments...
I have had several Vetus units catch fire. This occurs in a surprisingly short time when the water supply is cut off. (Say from a bag over the intake or something). They don't seem to light the surrounding boat on fire, but they do burn, and make some really nasty fumes while burning. Should the water come back on, well then we have a taking on water problem. They also seem to have a tendency to crack as they get older.
Neither problem have I experienced with the Vernalift.
Also Vernalift is available in a lot more configurations.
Guy