I like any chipset that works and keeps working. Boards that you can tweak and play around with are awesome but only for the first few days/weeks until the novelty wears off.
The iStick 50W is 4400mAh, that mod was certainly ahead of it's time, weird that there aren't more mods like that out there these days.
The Cube and the Rim are both good choices for a replacement despite their smaller capacity, both small and compact and comfortable. I'd lean towards the Rim...