I tried in vain to find a shop within 100 km of my home that has any square-neck dobros under €1k. Eventually I decided to take a trip out to Thomann, Europe's largest music store and test these instruments:
- Gretsch G9230 Bobtail - €769
Recording King RR-36S-VS - €399
Recording King RR-75PL-SN Phil Leadbetter - €599
Recording King RR-60VS - €679
First hitch - all instruments were tuned open D! I asked if this could be changed and he was a little nervous but came back with one guitar in open G - almost! He put it in G low bass

Gretsch: Dark, gutsy
RR-36S: Muddy
RR-75PL: Even, throaty - physically lighter!
RR-60VS: Even, dark
Make of those what you will! The main surprise came when I realised the Leadbetter model had a nut-width far slimmer than the others. At first this bothered me but I soon got used to it. I quickly established that the cheaper RK had no character whatsoever and parked it. Although I liked the Gretsch initially, I found it too dark and bluesy for my taste. So it was between the Leadbetter and the RR-60VS - the former's string spacing an initial blocker but I preferred it tonally. Then I hit what I guess you can call a power chord. My National really reacts pleasantly when one hits the strings hard. The Leadbetter reacted (but nothing like a National) and the RR-60VS broke! Literally it started to rattle and buzz, loud enough to annoy me; clearly I had dislodged something in the cone or tailpiece construction. I revisited the Gretsch but couldn't lose the feeling that it was a blues instrument:
My tests included different picks, different tone bars, use with a Beard capo, ease of changing tuning but primarily tone and playability. I had "rehearsed" a few pieces: a fiddle tune, some bluegrass standards, a Josh Graves tune and applied these to each instrument (albeit, adapting to open D!)
I went with the Leadbetter model because of it's tone, lighter-weight (I cycle and use public transport a lot!) As I was buying directly in house, the Leadbetter cost me €580 which basically paid for my train ticket. After a few days at home, the string spacing isn't an issue.
So there you go, that's my test results. Hope this is helpful to anyone considering these instruments.