Sounds like you've already made up your mind (and I support your decision), but since I actually have some of these in my tank here's my two-cents worth.
- they don't look like real holey rock at all up close
- they don't look horrible either
- they do accumulate algae easily, so if you want to maintain them as white, the manufacturer recommends power washing them occasionally (I don't bother)
- I've had mine at least 2, probably 3, years. They're holding up well.
- they sometimes aren't weighted correctly or the way they're shown in the picture so they might not sit the way you want in the tank. I just let mine settle however they want within reason.
- they are really easy to remove which is 100% why I got them. I HATE removing all of the rocks in the tank to chase a holding female....it's much much much easier with these.
- no big dead-ends for a fish to get trapped in (one of my big pet peeves with most aquarium decorations).
- if you lay the small and medium ones flat on the bottom, it makes some great spawning territory or cover for shy fish.
- they don't alter your water chemistry, so depending on what you're looking for, that's a plus or a minus.