As a relatively new member to the straight shaving community -less than a year - I understand the dilemma you're facing with the purchase of a good first razor. Obviously the overwhelming response from the seasoned pros is to not buy the razor in question, but I would like to share some newby advice that might help a little bit.
I fretted over the decision of a razor for a long time, and I've come to realize that it was all in vain. Once you accept the fact that there's going to be a learning period with any razor, it's not too critical what exact blade you're using (assuming that it's a quality blade). I started with a semi-ground 5/8 Aust which I like very much. Since then I have purchased a 7/8 Aust, and borrowed a 5/8 full ground Aust. Through my experimentation I've learned that I like them all equally. Sometimes I like the heavier weight of the 7/8, but other times I want the lighter 5/8. I wasn't a huge fan of how the full ground flexed as I used it, but I still had no legitimate complaints.
The common thread here is that if you spend a little bit more on a quality blade, you're sure not to be disappointed. In the beginning any razor you get will be able to outperform your skill as the operator. It's likely that you'll eventually want to get another one anyway, so don't sweat the decision too much.
I hope that helps, and good luck. It's totally worth getting over the learning phase.