Disclaimer: THIS IS NOT LEGAL ADVICE.

Either options would work great. A few things to consider:
1. Tax consequences of each (this is likely the biggest factor in your decision).
2. Stock grant purchase price is it consistent with your hourly/project rate.
3. I would recommend the stock be issued to your C-corp for liability purposes and tax. (is your partner working on the project a shareholder in the corporation?) another option would be to set up a separate entity to receive the stock.
4. Are you receiving any compensation; is there any opportunity to defer a portion and receive stock as the other half?

There are several other ways to structure this type of transaction that could work for both parties. I strongly recommend speaking with a CPA and a local attorney to advise you further. It would be worth the investment in the long run.

Good luck.