I only own the Metal Worx Curve. That being said,
I love the thing to death.
It holds cool or warmth for quite a long time. About 5 mins of soak is about 10 mins of staying power.
Both ends are pritty fantasic.
I use the muilti. balled end as a warm up. Every single bump hits the spot.
When you flip the toy over to use the other end, it may be slipery but the bumps act as good finger grooves.
The large bulbed end looks small, but when inserted it covers my g-spot and then
some. (but that's just my anatomy, every-bodies different)
What I find most interesting is the curve on the one balled end. It has a low arch that pushes down the floor muscles. Quite a pleasant feeling.
I'll write a review on this toy one day....
Hope this helps, if you have any questions just ask!