If you buy name brand, they should be very reliable! And the light output is awesome, probably outshines the H4 conversion. And mine were a plug n play operation!
1973 Bronco, 351 SEFI, Locked, discs, 35's ZF-5spd and Atlas 4spd. 235:1 Crawl Ratio. It may be ugly, but it's slow. http://www.ucora.org