to the OP.. recently i was faced with the same decision you were.. i knew i wanted a honda CB, but what?..
i was looking at 350s, 450s, the 550, and the 750... i quickly eliminated the CB750 because i wanted something lighter and the 750 was just too heavy for what i was looking for (for a touring bike, perfect, but i wanted something that would perform even better as a commuter)..
so then i started looking at the 550, 450, and 350... the 450 and 350 are gorgeous bikes too, and i intend on adding a 350 soon.. but although would be completely awesome for a commuter, didnt offer me much of an option for longer road trips... smaller engine, two cylinders more vibration, etc
so then i was offered a 76 CB550F.. had no tank, no seat, no front brake, mismatched wheels, and no electrical system... but made a great all-around bike for commuting, daily riding, touring, anything i wanted to do... so, this thing hadnt been started since sometime before 2001 when the last owner sold it, and apparently it was sitting around for quite some time before then
so i cleaned out the carburetors, changed the spark plugs, spark plug caps (couple caps were bad and quite possibly the reason it sat, leading the owner to overlook them and assume it had a bigger problem)... after that i pretty much wired the coils directly to the points system and to the battery.. then kicked the kickstarter... on the third kick it fired right up, no missing, no smoke, no sputtering, just ran hard and strong after the third kick after sitting 10+ probably closer to 20 years
should answer the question of reliability