Shopmaster Tri-power basically a DIY at this point- can we talk bearings?

So I have a small shop used for prototyping and have gotten some good use from my Shopmaster with some coaxing over the last decade. 90% of my use has probably been manual and of that, another 80% probably lathe. I'd always meant to update to ball screws and just now getting around to it- it started with the Z because I've ALWAYS hated it, but now I'm far enough in and the Z turned out so well that I'm doing the other two axes- starting with Y, I went with the imported ball screw kit from TEN-High, this is the same one I used for the Z which is repeatedly giving me .001" accuracy with almost zero backlash now. (unlike other axes, the Z rotates the ball nut- the ends of the screw are fixed).
I had lower expectations- though this isn't in use testing, just reading off the DRO, so of course I expect some variance in use.
Anyway, lots of folks talk about rolled vs. ground screws- but I've found much less discussion of bearings which I'm learning can be quite a big deal as well. The kit I picked up uses a set of bearings which seem to again be exceeding expectations as they're not identified as anything special or matched so I presume they're whatever's cheapest given the low cost of this kit. I've read some reviews where guys are obsessing over bearings and spending $1000's just for those.
I'm thinking of doing my X axis (longest) with at least upgraded bearings now, but only to something like a matched pair of angular load bearings, maybe Abec 4 or something? Anyway, I'd love to hear some opinions on the value of investing in bearings for a machine like this that gets occasional use for prototyping (assorted materials- occasionally steel) rather than regular industrial.