Yup. You can verify by yourself, if you like, comparing data from the time openSUSE still recorded unique IP's, see our statistics wiki and the Fedora one. Let's say we compare openSUSE 11.0, 11.1, 11.2 and 11.3 in week 23 (the common denominator between the Fedora's):
(btw that's a scary downward trend. if you go a little further in the weeks you see it's not that bad, our users seem a bit conservative in moving over to 11.3 especially)
Fedora had the following numbers in week 23 after the releases of 10-14:
In the graphs that we have in the blog you see a similar (or even bigger) gap. If we then assume everything is similar between Fedora and openSUSE we can probably say that openSUSE has something between 20% and 40% more users than Fedora but with the differences in release cycle and other biases I wouldn't be totally surprised if the distro's are even closer or if the difference approaches a factor 3. I would find it surprising if there was an order of magnitude difference in user base size or if Fedora would have a far larger user base as openSUSE - I don't think either of those statements would be realistic.
If you look lower on the page, you see that these numbers overstate the number of unique cookies for openSUSE by a factor ~10, hence my statement that IP addresses probably are about an order of magnitude off. I suspect that is how Mark Shuttleworth came up with such huge numbers of users - many, many millions, if I recall. Just unique IP's doesn't mean that much.
Of course, the nr of cookies that connect to a server in total is less interesting than the number of cookies which does so regularly. That last is the most reliable guesstimate we have of our user base: about 440.000 users, again, half of the cumulative nr of cookies in total. That might put Fedora on 280-380K users. But all this is dangerously close to pure speculation :D