Excuse my ignorance is E&Y Earnst & Young? If so, I shudder to think of their fees relative to an °µÍø½ûÇø teacher's salary. Maybe OK for those of you working for a multi-national in the Bitexco Tower or along Le Loi. Â
As far as Turbo Tax, I used the downloadable versions while in Vietnam, just as I did for years and still do. Actually, I first used an MS-DOS version starting in the 80's on an IBM XT clone. I personally won't use the online version because I don't like the idea of posting my taxes to "the cloud" which is just another word for someone else's hard drive. Â
TT can handle the overseas income exclusion (Form 2555) just fine. This is the one that may be of concern to most °µÍø½ûÇøs as well as Form 1116 for taxes paid to VN.  Of course it can handle any "normal" investments (i.e. rentals, stocks etc.) you might have in the US. Most major brokerage houses let you download your Form 1099 online. Be sure to buy the correct version. They tend to be a little sneaky and drop features so that next year you have bump up a version. Not sure but I think if you find you need to go up a version, you can do so at a discount. Generally speaking my taxes as an °µÍø½ûÇø were a lot simpler than they were when I was a farmer.
One area where TT gets weak is if you have to file a FBAR (Foreign Bank Account Report) as well as Form 8938 on bank accounts in VN that have a balance over a $10,000 equivalent. The FBAR is an anti-money laundering form and files online separate from taxes. Form 8938 files with your taxes. TT will ask you the questions but it may tell you that you have to fill out the forms yourself.  The 8938 is downloadable on the IRS site.  There is renewed interest in overseas tax havens, more like for multi-millions and Cyprus banks, but not filing when required could be risky even if we are small fish. Don't hold my feet to the fire on this but I think you can legally avoid the FBAR reporting by breaking up your deposits into different banks.  Given the state of banking in VN that might not be such a bad idea anyway. 
For those who say "I have been away from the US for 10 years and don't intend to go back," remember that you must file even if you owe no taxes.  Only formal renunciation of citizenship gets you out of filing, and that could be sticky as VN is not going to let you be a citizen unless you are Viet Kieu. You could get stuck with no passport at all.