Yes — shooting RAW can still be worthwhile in iPhoto.

With iPhoto ’09 and later, RAW files can be used effectively enough to give you real benefits, especially better white-balance adjustment and more room to recover highlights and shadows than with JPEG. So if those are the limits you’re running into now, you should notice some advantage even before moving to Lightroom.

The trade-offs are the usual ones: larger files, fewer shots per card, more storage use, and a slightly slower workflow. Also, RAW images may initially look less punchy than your camera’s JPEGs because the camera applies its own processing to JPEGs.

Whether it’s worth it depends on your needs. If you often wish you could correct white balance or exposure more flexibly after the shot, RAW in iPhoto is a sensible step. If you’re already happy with your JPEG results and rarely need extra editing latitude, it may not feel worth the hassle.

A practical approach is to shoot some test images in RAW and see whether iPhoto’s adjustments give you enough benefit. You can always move to Lightroom later if you want more control.