That's a tough call. I've been to both resorts a number of times, and I prefer Bandon hands down, but I'm more of a hard core golfer.
Weather wise, according to Weather.com, the average high in February in Bandon is 56, and 54 in Pinehurst. But Bandon gets almost 8 inches of rain in February, while Pinehurst gets less than 4. And wind won't be a factor at Pinehurst, but you can count on wind in Bandon during February that will make it feel colder. So if you're worried about the weather, and the deals are good, I think Pinehurst might win.
If you really want to improve your odds, to further south down to Kiawah Island...the Ocean Course is terrific, the weather will be warmer than Pinehurst and it's even less likely to rain there in February.
Rob