The rings are similar but the difference is in total diamonds used, and sizes and metals offered.
The 'original' option has fewer diamonds (check the diamond ctw on each), the newer ones are much more 'diamond packed'. However, with that is a higher price point.
The newer models are offered in Palladium, vs the original only white gold. Both are offered in Platinum.
Finally, the newer ones were made with two different size models which means we can handle ring sizes below size 5...the originals were made at size 6.5 and could not be sized down below size 5, so many asian customers were not able to order.
Anyway, those are the main differences...as you noted, they look initially simmilar but there are underlying changes and improvements which was why we made the new models
Hope that helps