I don't know much about stage 1/2 comparisons between the two, but I do know at stage 2+ that there has been a handful of people disappointed with the Revo software.
It's all about the power delivery and drive-ability of the car after it's been mapped, rather than the figures from a dyno lottery, however when some Revo owners have only been getting 330bhp at stage 2+, which is 30bhp less then APRs (and custom mapping tuners) gains at this level, then there is clearly something not quite right. It may just be that in these rare cases it was the tuners fault, either in not setting up the map correctly or the RR was incorrectly calibrated, but it could also be down to the software. Others like S3Alex have found that Revo have not updated their S3 8P maps for several years now whereas APR are still working on them.
Revo and APR are the most expensive maps available and as you've already had to spend several hundred for the Revo stage 1, upgrading to stage 2 and 2+ will now only cost you £60 at each stage (excluding the garages labour charge), whereas if you now changed to APR, then you would have to pay full price again. So really it depends on your budget and how far you want to go i.e stage 2+ or 3 with bigger turbo etc. To be honest I'd probably just carry on with Revo and see if you're happy with your gains at each stage, if you aren't and haven't got it RR to see what figures it is at, then get this done and go to APR if you think you could still get more out of it.