Well I can share my experience of using a 4/64 tablet with a weaker processor.
4gb is a windows sweet spot. You'll get really noticeably better performance than 2gb, but not all that noticeable difference from 8gb. You'll have to do some heavy multi-tasking, or heavy tasks to notice much of a difference, and even though I open 20+ tabs on my desktop browser, I never tend to do that on a tablet anyway.
eMMC is slower. But for the most part, it's only noticeable in certain situations. The biggest is large file copying, and installing or upgrading windows. You'll feel some delay there, it'll take about twice as long as SSD. Maybe a slight delay also when opening something heavy, like a power user application (say an adobe product), or a game. But for everyday performance, not so much. There is a speed difference, but it narrows on the key metric between SSD and eMMC - small chunks of random read/write, and on this metric eMMC is significantly faster than a conventional HDD. So for your every day light apps, UWP etc - it really doesn't make much difference.
It also helps for storage capacity on models like this you can get SD cards. You can if you like throw in a really big one, and because the bus is usb 3.1, you can likely get similar speeds to the internal SSD if you buy something with the speed rating. 64GB ones are a fair bit cheaper though ATM, and above 128gb you start to lose value per dollar.
Now this is all on an atom tablet where I can, believe it or not run some games - trine 2, tyranny, need for speed most wanted - some power apps - adobe illustrator, fruity loops. The Pentium is quicker than an atom, and closer to a core-m, so I think some of these things may be noteable quicker on the go. The newer intel graphics chipsets are pretty beast too for inbuilt graphics cards. So that may open up a lot of games that atoms are incapable of, as well as make the graphical experience/UI quicker. I think the pentiums also have more threads than atom? Not sure, but if that's true it'll kick up multi-tasking performance.