Considering Eheim Thermofilter

["Newcomb, Lew" <lew_newcomb at eds.com>]

I'm considering buying an Eheim canister, probably the Professional II,
model 2026 or 2126.  I love the idea of having a heater in the filter (2126)
instead of in the tank, but the increase in price is significant (~$55).  A
comparable heater by itself would cost about a third of that difference, so
I'd clearly be paying for the integrality.  Has anyone examined that
advantage/cost ratio for themselves?  What conclusions have you made and
why?   Thanks!
Lew Newcomb