Have done this before with normal compost but this time I thought I'd try the proprietary compost. Looked on amazon and at garden centres - there's a few choices (westland, miracle gro, one in a brown bag is it focus? and another I can't recall) but all of these have negative reivews on Amazon. I know it's not all about negative reviews but I was surprised that many of them seem to have small bugs growing in them.
I have yet to have anyone's first hand experience of using any of these composts (other than the reviews) so if you have successfully repotted cacti can you let know what you used.
Pardon my naivety, but don't cacti grow in the most driest, inert and lifeless 'soil' known to man? I wouldn't have thought something like a general bag of 'Arthur Bowers' was the stuff for them??
I don't know if I just got a bad batch but the last time I bought Miracle Grow compost (last Spring) it was full of lumps of un-composted vegetation...horrible stuff.
Cacti need a very gritty free-draining compost and one that's not too high in nutrients. You'll need to buy special 'cacti and succulents' compost or mix your own, to get the best results. There are vids on Youtube about it. When cacti are happy and flower well, they're amazing - but they do need special treatment.