My Adco E-Dot has never failed me. It is bright enough to be seen in the Arizona sun. It's quite a bit more expensive than similar
models, but it's the highest quality and is actually warranteed against paintball damage. I've heard the BSA red dots are a good
quality clone of the Adco E-Dot, and work perfectly well even in bright sunlight. Tube sights generally work better than holo sites on
bright days because they are enclosed and cannot be washed out as easily. For night play, the NCStar sight works just fine. If you
get an Adco sight, be sure it's the E-Dot. Adco makes other sights that are much lower quality. The E-Dot is the one you want, or
you can get the 30mm or 50mm BSA clone for much less money.