I owned the 200mm F2.8 (non-L) once, it was a fine lens. Raid is right about L Canon lenses. They use Fluorite glass which can be used to make exceptionally well corrected lenses, with particularly fine color rendition. The Canon L lenses are also exceptionally expensive!
Canon L1, Leotax S, Bessa R2C, Konica Autoreflex, Canon FX, Pentax Spotmatic, Minolta SRT-101, Nikon F, Exakta VX, Miranda Automex II, Leotax K3, Yashica Mat LM, Leotax S, Pen FT, Rollei 35S, Ricoh Singlex TLS, Kowa Six, Pentax K1000, Canonflex, Praktina, Voigtlander R2C