I really liked this series though i watched it partially out of order and only later got to see it again mostly in order. So i saw plenty of episodes with Sheriden before i saw any of the first season with Sinclair. I think the episode where the B4 gets taken into the past was one of the first i saw but thankfully im the kinda person who doesnt mind spoilers and its not like i could tell at the time which bits of the epsiode were spoilers.
I liked Sinclair, more than Sheridan i think, its a shame he couldnt have been in the series more. Ivanova was great and Marcus and i really liked the character of Neru for some reason even though he was usually antagonistic to Delen and the others.