So my thoughts after 12 hours with this mod (6 of them sleeping)
I bought the X as I wanted a backup/2nd pulse 80w. I bought the kit for the specific reason of trying the new RDA.
First the color - it really is not red. It is more violet/purple then red. The purple drip tip that came with it is almost a perfect match color wise. That said I do like the color so no complaints, just wanted everyone to know who has not seen this in person.
The Mod is 1mm wider than the 80w. the battery compartment is also much deeper and wider - i do believe the change the design to accommodate an 21700. It looks like it will fit one, but I do not have any, so take the word of those that do (earlier in this thread). It looks like it they are saying this is a very tight fit for one, which is too bad as I was thinking about picking some up, but with my .25 build at 45W 1 20700 = 1 bottle of juice and I am fine with that. I was happy with the 80w with this.
The rest of the mod is the same as the 80w. Same features as in the latest update and look 90w. Holding it, I do not notice the difference between the 80w and the x (I cant tell visually either unless they are side by side) but I have big hands and both mods are small to me. I really do love the feel of the G10 material.
First thoughts on the RDA - I like it (as of now). It seems to have a smoother airflow than the pulse 24. It was very easy to build on surprisingly (I was expecting it to be a pain). The well is very deep and you can fit a lot of cotton in there if you want. I have not yet over squonked - something I did within 10 minutes of owning the 24.
I am still within that first week of a new shinny with it, so before I go jump off the deep end and order 10 of them, I will be taking a few weeks and running both the 24 and the X with the same build, same juice, same wattage and see which one I am reaching for more.
Any questions ask away - I will answer what I can.