I'm just sharing what I've learned with others. A lot of this info is scattered about and discussed. This is a summary and a few of my own thoughts sprinkled in.
I tried two early 6.1 ROMs and didn't like them, too different, too much stuff I don't need. All I want is a Stock Sprint ROM with GPS and Rev-A. So I abandonded the cooked ROMs which are mostly 6.1 as far as I could tell. But doesn't matter the only one I'd be happy with is one I cooked myself and I'm too lazy to do it.
So I was running 3.35 Titan Radio with the AllTel 6.0 OS ROM (thought that, that would be pretty basic). It was pretty close to perfection for me and I could live with it for while. But it had some issues. Note that a of the little fixes I this round could have been applie to the 3.35 Radio with Altel OS ROM combination.
Observation 1: Data Connection not going down after long idle state like Stock SPrint ROM. Not a huge deal but I think it's slightly using more battery if I leave it like that. Not a huge deal but annoying.
Observation 2: It bugged me having the thick bars on Voice Signal Strength Meter. I think after running the Sprint Customization.Cab it fixed it. I'll know for sure when I see 5 bars. I can't even remember now how many bars was max but it looked wrong and now it looks right.
Observation 3: Very Minor the "Wireless Alltel" connection gave me a scare helping a friend with his phone until I noticed it on mine (both sprint phones). When you run the Sprint Customizations.Cab it fixs that.
Observation 4: ##CODE<Send> is a known work around for programming phone but running SprintCustomizs.Cab fixes that too so it's ##CODE# again.
Observation 5: Anyone else notice that they get a Notifcation Error right when the 3 second Custom Dialog pops up after a Fresh Flash. But if you Hard Reset again, you won't get that error !!!
Observation 6: Running PRL 60711 seems to fix slow Voice Radio start up after soft reset. As soon as I put 60610 back (thinking it might be more stable) I immediately noticed the really slow Voice Radio lock again. Try it, you can always switch back.
Observation 7: I swore up and down 3.35 Radio improved GPS Lock. Not sure any more. Placebo/Luck of the draw.
Observation 8: No ROM seems any different than another when it comes to Data speeds. Except original Sprint ROM may be slower, never measured it tethered before.
Observation 9: I read some of the threads on second round of GPS driver DLL's. But I noticed there is a lot of confusion between that and AllTel Users that need "KickStart". The new round of driver DLL's (and CAB) have "Extra" DLL's that I think are for Kickstart that Sprint Folks don't need. So I only replaced the sames DLLs we initially installed and did that by hand. I had to rename old ones in order to overwrite them. Don't know how good new DLL's are yet. Crossing fingers.
Observation 10: My device totally locked up at the end of a BT Headset call. YIKES I've never had that happen. It's gotta be a stable phone first and GPS/REV-A is icing on the cake. This is what prompted me to try something else.
Observation 11: Also I don't see documented that when you put .40 Unlocker back for 3.35 Radio the phone is very unstable until you put 2.31 Unlocker back. Not sure if it's putting 2.31 back or a 2nd round of hard resets. Saw the same exact problem when helping a friend. Put 2.31 Back after installing ROM.
So I tried to go to the Simplest solution. Just run the Altell Radio (3.37) and the Altell OS ROM (i.e. just run that hugely named .exe) and cross my fingers.
Standard Procedure with a couple shortcuts and suggestions: This is for SPRINT
1) Already had 2.31 Unlocker loaded.
2) Synced up
3) Run the AllTel ROM .exe
4) SKIP CUSTOM STEPS (You will see a Notication Error)
5) After booted HARD RESET AGAIN
6) SKIP CUSTOM STEPS (You will NOT see a Notication Error)
7) Run the GPS Unlocker Scripts and CAB

Reboot
9) Install GPS DLL's (CAB)
10) Before rebooting overwrite them with new DLL's so you won't run into them being locked (Only Replace don't add any new DLL's)
11) Run Sprint Customizations CAB (Highly recommended for Sprint ONLY folks)
12) I did put back PRL 60711
I know this won't fix all my issues but I'm hoping it fixes some. Mainly that BT Call Lockup.
Only time will tell how stable it is, but it sure looks and feels like my Stock Sprint ROM. GPS seems as fine as it could be. I only use Google Maps to Prime. And iGuidance is running great through GPSGate. Crossing fingers for no more GPS hangs (after long standbys). But I that the 3.35 Radio with AlTell OS ROM was my last flash for while too.