Which is the better investment?

That is a good question that requires you to take a look at the big picture of your finances. The first items you would want to ask yourself would be are you heavily leveraged? i.e. mortgage + carrying balances on credit cards, auto loans, ect.

If yes I would proceed to reading a book from Dave Ramsey called The Total Money Makeover. It will help you prioritize your goals and your tax refund would be best served making sure you have a good cash emergency fund first, then applying any left over cash towards paying off your smallest balance debt.

If the answer is no on being heavily leveraged. i.e. Mortgage/Rent only then you would be best served by ensuring you have a good emergency fund of 3-6 months savings in place and then looking into your investment options. Which the book Total Money Makeover also has solid advice in that area as well.

accounts receivable financing; no contest

Investment in Real Estate has got tremendous opportunity of great appreciation in the years to come.

Realstate: Buying physical land or property.

Stock:Buy piece of companies sell furniture,motor cycle,create videogames or provide tax service.

The s&p500 index is up nearly 5% ytd. And was up nearly 32% last year.

You don't mention what you've invested in (other than stocks), but maybe you should find a good mutual fund??

I bonds are paying almost nothing.

Educate yourself more on stocks, learn from your mistakes, then if you feel like you can't take the risk, do something else. This is America, you only live once, don't expect a lot of reward without risk. Be patient with your stocks too, I reccomend Louis Navellier to help pick your stocks. Don't go with weak interest rate bonds. I reccomend a mutual fund if you can't take the risks of stocks, or a 401k, your money, your decision.