The OM-1 and OM-2 are indeed in many ways actually better-built than the OM-3/4 - anybody who's ever held one can tell. Smoother and possibly more solid. They were professional bodies, built to last. The OM-3/4Ti are just famous for having actual weather seals protecting the electronics etc, but they are not any stronger than their predecessors. My OM-3Ti lightly fell half a meter onto a tile floor (the joy of Cats...), and its (plastic) internal shutter speed coupling ring was buggered, needing replacement. I had to salvage one off an OM-2SP.
Also, the OM-3Ti and OM-4Ti had revised circuit boards that completely solved the battery drain issue of the earlier (plain) OM-3/4. Mine goes for almost a year with moderate use - who could ask for more? Of course, when the batteries in my 3Ti dies, I just go on using it :)
Anyway, the OP should hopefully have some insight - but not as much as just giving them a try. Granted, an OM-4Ti is not easy or cheap to get hold of, but not impossible either. The real magic lies in the more interesting Zuiko lenses, however. Especially the wide-angle lenses (like the 21mm f/2.0 here) are particularly excellent, better than anything Nikon had to offer: