Well, I have 2 SQ basses , and used to have an E series Strat, so, I guess I'll chime in...
The body probably is basswood. Not that there's anything wrong with that. Different models/finishes seemed to dictate, but most I have seen seem to be basswood.
The electronics may be of a "cheaper" type, but that doesn't mean they'll sound bad. Easily replaceable regardless.
Be sure the truss rod is functional, and that all parts are working/present. If not, haggle. I got my SQ J bass for cheap this way. Just be confident you can fix what's wrong, or have it done, for a reasonable cost.
If it's anything like my SQ J bass, and most MIJ Fender/Squier J basses, it'll likely have a grounding strip between the bridge and the bridge pickup. This is easily done away with if it bothers you. I left mine alone.
FWIW, bases on the many E series j basses I have seen, and the very small number of SQ J basses I have seen, I think the two are really pretty similar.
In that spirit, I will say that the neck on my J bass is lovely but thin (but not Geddy thin), the electronics are effective, capable, and sound good, and the body is a J bass. I put a vintage threaded saddle bridge on mine, and a Hipshot tuner is next.