more expensive likely to mean better option to take. Astro has very few cheap quick wins. I haven't used guiders yet but I would assume you would benefit from quality optics for better crisper stars for the guider to use plus a flatter field of view likely to be desirable for accurate plate solving. Just going on my experience with plate solving my images some have proved impossible so far and some dead easy to solve.
I would also assume a guider works better on smaller single stars so aligning ota and guiderscope to same point should be less desirable as you usually want a large bright object in your view which would be more difficult for a guider to pinpoint.
I did same assume remember. Happy to learn my assumptions are wrong before I get itchy to spend on gear