alex...
I am on the downside of 40 and I still am not sure which way would be better.
I read this to mean you are closing in on 50, not 40. If so, yeah, you are in a gray area. The thing is, a government guaranteed benefit is unbeatable in regards to safety. Unless the law is changed later on.
Given all the changes to SS since it's inception I think it prudent to count on change. What kind of change?
In 15-20 years the boomers will be a tremendously powerful political force and the reality may be defecit spending to get you and I (I am the end of the 'boomers') through to old age. BUT we will live longer, probably average into our mid/late 80's by then...or more.
THIS IS ALL THAT MATTERS: When we're gone, there will be relief to the system but people are only having two kids these days. That math could get no more simple: 1 mom, 1 dad, two kids and maybe their 4 to take care of the old folks. 4:2, 2:1. Four paying two, two paying one in a Ponzi scheme which started at 22:1.
It's bag holding time. The rest is conversation of 'how'. Not 'if' SS dies.
If nano technologies or other things emerge along with never ending advances in health and medicine, we could be looking at repairable hearts, lungs etc. We could be looking at clear minds and useable bodies at 80 plus years of age.
The downside is, obviously, living longer straining the system even more. There is no limit to SS. As long a you are alive, you get paid.
The upside is, what the hell, the ability to work.
So, some thinking about what the future may look like can help but the very first step is agreeing, all of us, based on SIMPLE math of how many kids wer're having is this: SOCIAL SECURITY IS DONE. It can NOT work any longer.
Any one resisting change now is a petulent child and will find themselves not part of the solution. The good news is as stupid people and their representatives further remove themselves from the debate, the solution will be that much less polluted with the opinions of people who refuse to face reality.
Go here:
http://www.bloomberg.com/analysis/calculators/retire.html#results
Get out your SS summary. Play with the numbers. See what you're slated to get. Now, understand that won't happen. It can't. Do some scenarios where you sacrifice part of what you're apying now to take care of our elders and see them through the system they are depending on. See what you could do with the rest at 4%. 6%. Take a look at the gap needed from our young'ns to close the gap bweteen what you are now promised and what you could OWN if you could invest it. Take a look at how far PAST you could be under fairly typical historical returns.
A first year Wharton Business school undergrad could take all the tables, population growth, age, % of population in the program, projected personal income, inflation projections, GDP projections, market projections and in every scenario come up with a program that would exceed, for everyone, what SS would provide.
The dirty secret is if the market is so bad, the doomsday scenario, that a new plan wouldn't be able to meet todays projections, the fact would be that the economy would be so bad that the feds couldn't pay anyone anyway under the existing program.
So, it's not 'if' Social Security is laid to rest. It's 'when' and 'how'. This nation does incredible things when it is unified.
As I've said before, me, at 41, would happily keep 1/2 my 15%, continue contributing the other half and relieve the government of owing my ANYTHING when I retire.
The possibilities are endless because of ONE fact; SS is done. It can't work past the the existing generation of retirees.
I'll be one of the ones contributing so that I'll actually get something back when I retire! 
