What is the difference between a 100% stock dividend and a 2-for-1 stock split?

A 100% dividend means they pay you an amount equal to the price of the stock while you still own a share at that price.

For example Stock price = $100
Dividend = $100

You now have a stock worth $100 plus $100 in cash in your pocket.

2-1 split means you now have 2 shares of stock instead of 1.
When it splits the value goes down because more shares are on the market.

Pre split 1 share = $100
Post split 2 shares each worth $60 for a total of $120

see the difference?

What really attracts investors is a stock price the increases. Unless you are looking for income the dividend doesn't mean much. I invest for the long term so I want to see an increase in the stock price so I can make $$$ when I sell the stock.

There is no difference in the 2-1 and 100% dividend.  In accounting, a stock dividend of more than 25% is accounted for as a split, simply double the shares and halve the par value per share.  With a dividend, you debit retained earnings and credit common stock, but that does not affect overall equity.