I just received the #8w today, and I already have the #8. I quite like the #8, for the money, except for the side button. I hoped the #8w would be the same but with a bottom switch. That, as you all know, was not the case.
The #8 is more adjustable in the top cap, and can be easily set to have your atomiser sit flush. I've used both the RSST and the AC9, and they sit flush. They would really look great if they were the same diameter. The atomisers are a couple of mm smaller.
With the #8w, however, I have not been able to adjust it so that the atomisers sit flush. This is particularly glaring with the AC9, which has a longer stem. The gap is unsightly. I have similar problem with the 18650 tube and end caps. There's not enough adjustability to achieve a gapless connection on top and bottom. It's a very small gap, and not really noticeable, but the #8 does not have this problem at all.
If anyone figures out how to adjust the top cap to be shorter, please let me know. I looked at it, and there is a brass screw that allows you to extend it, but I need to go the other way and shorten it. The brass firing pin may be threaded, but it's not slotted to accommodate a screwdriver, so I don't know. I tried turning it, but with no luck.
One thing that did surprise me about the #8w was the minimal voltage drop right out of the box. I measured it at 0.2v with my RSST. That's up there with the Nemesis and Caravela for conductivity. It a hard hitter, indeed. The #8 by comparison, dropped 0.35 after removing the spring. Still very respectable for the money. It was a whopping 1.0v drop with the spring. Both mods have all brass contacts.
I also agree with the complaints about the bottom switch spring being too stiff, and the button is a little bit sloppy. So far it has never misfired, though, and I'm hesitant to mess with it considering the excellent conductivity as is. I just hope the spring will soften up a bit over time.