All of the Wula drums I've seen and heard have been very high quality. I'm sure you could just ask them what the differences are and they'd be glad to tell you. It looks like they may use a slightly less expensive set of materials to assemble the drum. 5mm rope instead of 6mm. Perhaps a thinner skin. If the higher quality is completely out of your budget I'm sure it would still be a great drum.
The guys at drumskull drums (
http://www.drumskulldrums.com) make a good point about quality.
<<<During your search for the perfect djembe, you may notice that there is not a huge difference in price from the low end to the high end price range. Generally speaking this price range may be an average difference of $200-$300 for the worst to the best quality. Compare this to the guitar market where a custom built professional guitar can easily cost as much as $5000 more than a novice version. The reason that this is so important is that though the price range of djembes is not large, the quality difference is.>>>
Another source for WULA drums on the west coast is
http://djembemandrums.comWho knows, you might save enough in shipping to go for the higher quality drum.
Have you looked into teachers or workshops in your area to help you get started?
Best of luck