I got my brand new E4GT about 3 weeks go, rooted it immediately, and it worked perfect for the first 2 weeks. After 2 weeks I decided to try a ROM (Blazer) and the next day started to have speaker problems, and call quality problems. It got worse and worse each day until it was impossible to make calls anymore. I thought maybe it was the ROM so I tried another one (Calkilin ICS) but that didn't fix it.
Yesterday I unrooted (thanks to QBKing videos) and went back to stock and the problem was still there. So thats good news, it wasn't the ROMs fault. I took it to the Sprint store to see what they could do. There is only a 14-day return policy. I thought it was 30 days, did they change that recently? Since it had been 3 weeks they charged me $35 to look at it. An hour later they told me the speaker/microphone/headphone circuit was bad and they were giving me a replacement refurbished phone. The replacement phone looks new so I guess I'm not too mad about not getting a "new" one.
The whole time they kept pushing their phone insurance on me. I've always thought it was a rip-off because at $7/month x 24 months plus $100 deductable, thats more than the $200 I paid for the phone. But I think I may go back and get the insurance for 3 or 4 months, and then cancel it.
Anyway, has anybody else had a speaker/microphone/headphone problem?? Of course the guy at the store said he had never ever seen that problem before...

 

I root immediately because there are programs I want to run that require it.
This is my third android phone and I flashed ROMs before and was much happier with the custom ROMs compared to the stock ROMs. Plus, I'm a smartphone nerd so it's fun (but slightly frustrating sometimes).
I'm 99% sure the timing of the speaker/microphone problem was a coincidence. Brand-new unrooted phones have problems and get returned all the time...

 

I returned the phone to the Sprint store and they replaced it.

Rooted and running Blazer ROM for a few days now. Working flawlessly...