I used to own a Rebop 5 and it was OK. The frets hung over the side badly and were rough on your hand. And, it had a bad case of neck dive, prob the worst Ive seen.
It's not really fair to judge Spector on fret-sprout that's caused by humidity/poor shop QC and can be leveled off by a competent tech in under 1/2 hour - I've played 3K+ Pedullas and pre-Gibson Tobias' that have had the same problem simply because the shops had the air too dry. As for the neck dive, it's simply 1/2 the classic small NS body design and 1/2 the lightweight woods used (an Alder body/Maple top) - you're right in that a decent strap will take care of that.
As for ReBops, I love mine to death (Avatar

) and ysand and I should have a ReBop GTG

: I've got a 4-string pre-DLX, a five-string fretted DLX FM, a five-string custom fretless DLX FM... and hopefully a five-string DLX FM strung EADGC to replace my six-string after I've paid off these latest purchases. I'm actually one of the few Spector fans that's
not a fan of the Euro/ LXs, mainly due to the neck-through construction: for my needs the ReBops with their bolt-on construction and body woods sound like "a Spector and a Jazz made sweet love down my the fire". Enough of the classic Spector "punch" without the high-end of the Euro mixed with the sound of a good Jazz bass (and even moreso when I finish my pickup mods, Nordstrand Big Singles and Aggy OBP-3s). Even the off-put TonePump isn't a
bad pre, (same for the HZs - I think people read "EMG" and are ready for its classic active sound, which the passive HZ doesn't do) simply too hot - they they dialed it back a quarter I have a feeling most people here who don't like it would and it would be the equal of an Aguilar OBP-1.
I've spoken to PJ and the guys @ Spector and the "Spector meets Jazz" tone was their idea with the ReBop from the start, so a direct comparison to the neck-through line isn't exactly a fair one - that's one area I think the company would do better marketing/informing players the differences between the models. To my ears the ReBops have the tone I spoke of above, as well as one "less compressed" compared to the Euro/LXs typical of a bolt-on compared to a neck-through that I've played... and my main bass for 5 years was a multi-laminate neck-through, very "Spector-esque" high-end Ibanez for sessions and live gigs. Other than that they're built in the same factory as the LXs, set-up next to the LXs in Woodstock, and one h-e-double hockey sticks deal price-wise both new and
especially on the used market. Whether 4-string or 5, I'd highly suggest you give it some serious consideration.