A lot depends on your age and whether you have the temperament to invest your money long term. Another issue is how much additional assets you have to invest.
As a rule of thumb - if you are over 55 - you probably will find it difficult to beat the guaranteed income from the pension. You could have someone run the numbers for you, but I have never found it reasonable unless you assume a very high return - 8%+.
If you are between 45-55 - you might do better if you can get a 8% return or higher. If you are under 45, then it probably makes sense to move it to the IRA and invest the money in a low fee, low turnover, highly diversified portfolio.
$351 may no seem like a lot of money to you - but, when added to your social security, it all adds up. I hope you are able to get enough info to make a wise decision.
Hope this helps you.