What software are you most comfortable with? I would start there and make list of what controllers work with the software you like the most and has jog wheels, then try to narrow it down to 2-3 choices. Then, if you still can’t decide, post again with the 2-3 you have narrowed it down to.
By the way, if you have a S8; then I’m guessing you are using Traktor. If you are, why not go to the S4. It’s similar enough to the S8 that you probably won’t notice too much of a difference, you get the jog wheels you want and you don’t have to change software.
If you want to switch to Serato, then your choices multiply. There’s a few posts on the forums about the Denon MC6000MK2. You may want to take closer look at it. It has 4 channel mixer, jog wheels, is still portable and has plenty of functionality. Plus it retails for around £400 – £500.