My experience is that you should consider an agreement with one tuner who will not rest until he sorts it out on road and dyno, then continue the relationship with lifetime free tweak / upgrade from anywhere by reading a log file sent via email. You can do that with both HP Tuners or EFILive but no brainer, better with the latter using an AutoCal IMO.
Having said that, Rob at East Coast is a young bloke with a clean setup who knows LS stuff, talks straight, I imagine as the owner he would be very interested to hear about BigDaddy's piss poor experience with his team personally. $690 is a keen price for opening Pandora's box and re-tweaking a custom dyno tune, then again may be clear from the outset.
Similarly I'm sure Ian at PowerTorque (Walkinshaw Brendale) would welcome the opportunity to review / explain the quote, it is a bigger setup with a full-time chick out front among other things that you wouldn't mind paying for if you drove an HSV / Walkinshaw badge. The flip side of paying a decent price for a decent job is that you sometimes get decent things thrown in, or service goes beyond the pale, as in my case when they threw in the underbody aero plate that was missing.
My experience is that you will get a much better deal as a walk-in with both blokes, discussing / bargaining the job in person. Especially so if you have a nice bottle of Eden Valley Grenache strategically positioned on the parcel shelf with Ian's name on it (knows his wines too).
Another young bloke I can recommend with a clean setup is Tim who runs Custom EFI and Auto Electrical (forum sponsor) but he's down whoop whoop (Jimboomba). Tim and his partner have a new Mainline and HP Tuners, low overheads and knows LSes.
Any of the above can tweak an HPT tune and run it on rollers, it is worth noting none if these use EFILive so it will cost same as full tune if that's what you have.