I said keep an open mind.
Strongly agree here.
OP:
So far you have one limited experience: a low-end Riedell kit was a good fit; and a low-end Jackson kit was a bad fit. Based on this one limited experience, the advice to stick with Riedell and avoid Jackson is not correct; especially since you will be upgrading from a low-end kit to separate intermediate boots and blades.
Boots are shaped on foot forms referred to as lasts. Ideally, you want to pick boots shaped on lasts that closely approximate your feet. There are no standard lasts. Different manufacturers use different lasts. A single manufacturer may also use different lasts for their various models; e.g., one last for boots in low-end kits vs. a different last for intermediate and advanced boots; or even different lasts for separate lines of intermediate and advanced boots (e.g., one last for traditional boots vs. a different last for lightweight boots to compete with Edea). A manufacturer may also change their lasts from time to time for whatever reason, or for no reason. So just because a low-end Riedell kit was a good fit and a low-end Jackson kit was a bad fit does not necessarily ensure that an intermediate Riedell boot will be a good fit and an intermediate Jackson boot will be a bad fit (maybe, but then maybe not). Also, as you progress in skating, the features that you want in a boot will change; and certain features that you like in your current low-end boot may actually be disadvantageous as you progress (e.g., many beginner skaters often find a strong heel lock uncomfortable, and beginner boots often don't have it; but you'll need it as you advance). So, I agree with Sunshine: at this stage in your skating, keep an open mind; consult with fitters, coaches, and other skaters; do your research, and educate yourself (as you are doing) ... don't walk into a shop with the preconceived bias that Riedell is right for you, and Jackson is wrong for you; evaluate them, and others, with a fresh eye.
I bought my first pair of skates decades ago. The boots were Riedells. At that time, they were really the only game in town. Jackson didn't exist, and companies such as Harlicks and SP-Teri were niche brands for advanced skaters. Many things I liked about Riedells, some things (such as the pointed toes) I didn't. Over the years I stayed with them (several models), because various alternatives had their share of flaws as well. And since I wasn't skating a lot, they were adequate. About five years ago, I semi-retired, started skating 5 days/wk, and signed up for private lessons. Time for new skates. My coach recommended that I consider Jacksons, and not automatically buy another pair of Riedells. I ended up with a pair of Jackson Elites. And I was really happy with them. The wider, rounder toebox, in combination with a narrower heel was just what I needed. The extra inside volume also allowed me to insert a corrective footbed, which I couldn't do in the Riedells: I could do without one when I was skating only 1 hr/wk, but not when I increased my ice time (up to 8 hrs/wk now). There were various other features (such as memory foam lining and padded top collar) that I really like. The higher heel pitch on the Jacksons did screw up my backward skating. Took a couple of weeks to adjust, but then I was fine.
As much as I like my current Jackson, though, I'm not sure I will stay with them. They've totally redesigned their advanced boots to compete with Edea. I looked at the new Elite, and didn't like the construction quality. My tech suggested I might want to consider Graf. I'll keep my mind open.