Stick with OEM bulbs. But buy them at the best price you can. I got a replacement bulb for my Panasonic PT-AE4000 from ProVantage for just over $300. It's an original Panasonic bulb, but it was about 1/2 the price of trying to buy one local.
P.S. I had waited until the projector was complaining about the hours before I replaced the bulb. But seeing how much of an improvement it made, for just $300, I will be replacing bulbs before their end of life-time in the future. It was just like getting a whole new projector, for 1/7 the cost!