The Aspire is not going to give you any benefits over the Spinner other than better looks. I have both and while the Aspire is far better looking, the voltage adjustment range is more constrained than the Spinner, plus the indicator on the base is much harder to read than on the Spinner.
I don’t own the Kanger, but have borrowed one from my nephew and found it to be about the same as the Spinner in terms of functionality.
If you’re looking to step up in terms of functionality and precise adjustment, but want to keep the size (and price) as compact as possible, I’d agree with the other recommendations about the Innokin MVP or the iStick. Both will give you more functionality than the Spinner. Of the two, the iStick may be more appealing since it’s smaller than the MVP. Still larger than the Spinner, but pretty compact. Both have internal batteries like the Spinner so you can charge them using a USB cable and don’t have to deal with the extra cost of batteries and a charger.