I have owned a MVP since day one V1 and am a huge fan but, I am really liking the ergo feel of the CFIV sooo much better. For some reason I was under the impresion that you also had Cool Fire and was hoping for a direct comparison. If it baisically feels and handles like the MVP and has the same battery life as the CF then I don't see a hole in my quiver for that arrow.
Well, I own one of each, so... The CFIV is smaller and lighter, while the Disrupter is similar in size and shape to the MVP 2/20W, although a little lighter. They have the same batter life... but, if you will be out longer than a full charge will carry you through, then you can bring a smaller InnokinCell battery with you instead of bringing two CFIVs. The Disrupter will fire up to 50W, while the CFIV does 40W. The display screen on the Disrupter is also larger than that of the CFIV. For you, Capt., I suspect that the CFIV will suit your needs more--unless/until a larger Disrupter battery is released.
The roles that the devices play for me:
CFIV: Will be my travel device when my dying vv3's finally kick the bucket (they have trouble lasting through a single Evod now, so that will be soon).
Disrupter: Will travel with me when I go on longer day trips.
MVP: My stay-at-home desk device.
SVD2: My backup device and the first thing I reach for if I hear an intruder breaking into my house.