I admit I don't use my OM Zuiko 75-150mm/4 very often, but I do love using it whenever I bring it out! I imagine it should be a similar experience to your FD Canon 70-210/4, though you've got quite a bit more range in yours.
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I have the FD 70-210 and the 80-200. Have used the 70-210 on my previous camera (Fuji XE1) and my EM5 and really like the lens. It's not that heavy and pretty easy to use. I prefer the 70-210 (is why I bought it back in my film days to use over the 80-200) because focus and zoom are on the same ring (the 80-200 uses two rings). You should enjoy it, I know I do.