Just to be clear, are you talking about about the Ray34? $400 is Ray4 (SUB) territory, which will not get you anywhere close to 85% of the "experience".
I'll defend my SBMM Ray34 with as much energy as I defend my EBMM SR4. First off I will make these disclaimers:
- My Ray34 is an early (2012) model that has been improved with Hipshot HB-1 'Short Key' tuning machines, although there were no problems with the OEM parts other than the aesthetic - I didn't like to look of the SBMM 'long' key. Mechanically I had none of the problems that seem to marr later tuning machines, although I believe these issues have now been resolved.
- My EBMM is also an older (1991) model, not the newer Special.
- They have both been professionally set up, including PLEK. I bought them both used so I can't vouch for how they were from the factory, other than to say the fret end finishing on the SBMM was not great - I had the edges rolled as part of the setup;
- the pickups on both have been changed to ceramic, but for reasons of personal preference, not for any fault or shortcomings in either OEM part. Both of the original SBMM and EBMM AlNiCo pickups were great and with no discernable differences - I just prefer ceramic in this application.
With all that said, there is so little between them (other than the obvious!) that I would really struggle to justify replacing the Ray34 with an SR4. The fit and finish on both is impeccable; the hardware, including quality of plating is comparable with no discernable differences; they both feel 'alive' and are really easy on the hands; they both make the entire range of sounds I need without compromise. IME, the Ray34, at least my example, oozes Music Man DNA and I am more than happy to play both side by side. I bought the SBMM in 2015 and it has been a solid issue-free performer since then, with almost daily use.
Minor differences include plastic vs bone nut and slightly deeper/sleeker body and neck contouring on the EBMM, but that's about it.
I will add that the (stainless) fretwork on the Specials is amongst the best of any production models I have ever played - you won't get that with any off-the-shelf SBMM model, IME.
YMMV