I recently completed a FERS retirement seminar.
Instructor said concerning Gov Annuities (Met Life) -
NOT
He said instead look at TSP Monthly payments. You leave your money, allow it to make money, while drawing monthly payments out.
For example look at the below information
With a beginning account balance of:$300,000 At an assumed annual rate of return of:8.00% (interest could be more or less) Paid in monthly installments of:$2,200 You can expect to receive the following number of payments:361 Which will deplete your account in:30 Years, 1 Month
Now compare this to the Annuity, I chose 63 because that is when i PLAN to retire.
YOUR ANNUITY ESTIMATE is based on the following information:
You chose: Annuity Option 3a (Joint Life Annuity With Spouse, Level Payments, No Additional Features, 100% to Survivor)
You estimated your TSP account balance at: $300,000
When you are age: 63
Your spouse or joint annuitant will be age: 1 Your estimated monthly annuity payments are: $1408 based on an annuity interest rate index of: 5.250%
Based on your election of a 100% survivor annuity, when either you or your joint annuitant dies, the monthly payments to the survivor would be the same as payments you are receiving at the time of death.
TSP Monthly payments is the way I will go. I am so thankful I attended the FERS retirement Seminar. I would most likely had made a terrible non-reverseable decision concerning purchasing the Annuity! Additionally you can still have control over your TSP account. I do think you can only adjust your montly payments once or twice a year, but you can still move your funds around.
If the above is incorrect, someone please advise.
DDT to answer your other question:
What happens to my TSP account balance if I die? 
If you die before your TSP account is completely withdrawn, the balance in your account will be distributed according to your most recent Designation of Beneficiary (
Form TSP-3), if you completed one (See "
How do I designate beneficiaries for my TSP account?"). If you did not file Form TSP-3, your account will be distributed according to the
order of precedence required by law.
In order for your account balance to be distributed after your death,
Form TSP-17, Information Relating to Deceased Participant, must be submitted to the TSP Service Office along with a copy of your certified death certificate.
If you are a FERS participant and you die before you separate from service, your beneficiaries are entitled to your entire account balance, whether or not you have met the vesting requirement for your Agency Automatic (1%) Contribution. If you die after the TSP purchases an annuity for you, your benefits will be provided according to the annuity option that you selected. If you die while you are receiving your account balance in a series of monthly payments, your beneficiaries will receive the balance of your account in a final single payment.
Payments made directly to spouses of deceased participants are subject to 20 percent mandatory Federal income tax withholding. However, spouses of deceased participants can avoid the mandatory withholding and defer paying taxes on all or part of their payments by having the TSP transfer the payment to a traditional IRA or eligible employer plan (including the spouse beneficiary's existing TSP account). To have the benefit payment transferred to a traditional IRA or plan, the spouse and the IRA or plan administrator must complete Form TSP-13-S, Spouse's Election of Payment Method.
Payments to beneficiaries other than a spouse are subject to 10 percent withholding; this withholding is optional. Non-spouse TSP beneficiaries can also defer paying taxes by transferring their death benefit payments to an "inherited" IRA and, in most cases, taking required minimum payments based on their own life expectancy. This eliminates the tax hit that many non-spouse beneficiaries were subject to before the Pension Protection Act of 2006 was passed. However, the rules governing "inherited IRAs" are complicated, particularly if the deceased participant is over age 70½. We suggest you discuss this benefit with your tax advisor or IRA provider as you do your estate or retirement planning.
To learn more about the taxation of payments following the death of a participant, read the tax Notice "
Important Tax Information About TSP Death Benefit Payments."
DDT
for finally giving me a reason to designate a beneficiary. I had not thought necessary since my designateds will be the same people that would get my account regardless. 
