We'll all be 'rooned...
I have known a few guys gone down the Rishworth track into RBA. Of course they take a hit of your pay while on contract. Welcome to the world of supply and demand. Once off contract things are different.
The guys with RBA that I know of have gone from regional (mainly metro, SAAB or B1900) to SFO with RBA to Capt within 2 - 4 years. Housing, etc all paid for and "almost" living off the allowances. I know SOs with QF who have been an SO for 5 years, and CX SOs for 4 years (max with CX though).
For this gig it seems the money for the Rishworth deal is about the same as an FO with DJ BUT housing is covered, and away from home allowances are are MUCH better. (No $200+ a week to rent in Syd as that is where the newer DJ guys are being based). The B777 endo is not $40k. More like between $30k - $35k (Aust), depending on where you do it. Therefore not much difference between that and a B737 NG if doing it o/s.
Direct entry FO on B777 flying long haul, international v FO with DJ (or JQ on even less $$$!) flying domestic. It's a personal choice up to the individual. Every person entering any job should be aware of the realities, not the hype or spin.
I know of the ONE person who did the B767 endo when asked to by Rishworth and failed to get offered a position. Other factors came into it that I am aware of, and not the fault of the driver in question. A big stuff up, yes.
To me it sounds like a good enough offer under the circumstances. Fly a B777 (amazing aeroplane!) for a few years, see the world. Come back to Oz experienced and type rated. "Potentially' not a bad situation to be in.
For the record, I've never worked for RBA or Rishworth, just know a few who have / do. (Getting older - never said wiser).