Thanks for the replies so far!
It sounds like people who use filter flosser or aquacomb are generally happy.
- For the flosser, I like that it is made of aluminium and the curved shape seems to make sense to direct the spray to cover more filter area with all streams "orthogonal" to the filter.
- For the aquacomb, the combs might be useful to keep the pleats apart. However, I would worry about damaging the filter. Still if the comb helps reach inside the pleats better than the flosser and than perhaps it is a point in its favor?
Do people who use the aquacomb make use of the comb or just spray without combing?
I'm still torn so any further insight would be great. In the end, maybe its just a coin toss.
(Ideally someone would have done a comparative review somewhere but can't find such a thing on the internet.)