That's pretty much the only make I use. The rapid is very rapid - sets hard enough to walk on floor tiles within 2 hours - and the standard is very strong. Both the SPF types are a bit flexible so good for chipboard or under-tile heated substrates.
Definitely not cheap but consistent and reliable. That's more valuable to me. I've tried a few other makes and have always come back to Weber afterwards. Not so impressed with the grouts - happier with Mapei there - but there's not much in it.
The new "low dust formulation" packs are a lot less messy to use and I now don't feel the urge to wear a mask while mixing! Probably still should, though.
I've used the SPF, both rapid and standard, on porcelain, travertine, granite, limestone and gres with satisfying results.