We have 3" recessed lights installed in one room spaced about 4ft apart and they light really well without being eyesores like their 6" counterparts. I will say they toe on the line of being too busy, but I think we get away with it. In retrospect, probably would've gone with 4" cans, but overall happy. Ultimately, how well they light will depend on beam angle, ceiling height, and can size. If you like to crunch numbers, you can design a few lighting plan options and choose the ones you like best, or you can hire a lighting designer. In terms of where to buy them, the best selection:price ratio is probably at Amazon.