I've never operated either brand, and I'm only a hobbyist so not part of the brain trust. But a shaper is a shaper. And like any machine tool, way surface condition and lack of wear is everything. Unless either of those shapers had working oil pumps or oil cups and they were always looked after properly, it's not unlikely to see scoring on the ram ways, highly worn bushings etc. Then check the Scotch yoke and bull gear assembly, any missing teeth on that bull gear would instantly kill the deal for me. Any missing parts, belt guards etc can turn a machine tool purchase into a large money pit even if you can find the used parts. Convenience aside, I'd always chose 3 ph over any single ph motor. But the Logan has one thing going for it the B-G doesn't. Parts drawings are available for it.
Dimensioned Drawing Set For Logan 8" Shaper Neither brand were built in the numbers the South Bend and A##as shapers were, so any used parts would probably be a whole lot tougher to find.
It took me a long time to figure it out, but smaller machine tools previously owned and used/abused by hobbyist's really ought to come with a fairly significant lower price level. My South Bend shaper and small horizontal mill both exhibit exactly what I mean with missing parts, wrong lubrication, neglect and ham fisted damage to some of the parts that are there. And both given there way surface condition, were used very little. No not all machines are like that, but a high percentage of the used smaller machines are. And if they've been sitting in storage for a long period. Then if it were me I'd fully expect to do a full machine survey just like what would be done before totally rebuilding any machine tool, make a list of where and what parts might need attention or replacing and pull the whole machine apart for a through cleaning, re-lube and re-assembly. My slides on both the shaper and mill were almost immovable due to contamination, incorrect and congealed lubrication. It's simply impossible to remove all that without a full disassembly. Where you are any home shop sized machine tools including shapers aren't all that common, $850-$900 despite being ridiculous for a small shaper is today well within the ball park numbers. The South Bends which are a fraction smaller and lighter built seem to average around $1200- well over $2k if there in good condition with a number of original accessories. Having the original vise is a big deal, milling vises used to replace a shaper vise are usually over sized in length and height compared to a the proper OEM shaper vise. I've no idea about what Logan 8" shaper vises are going for today, but I do know on average the original SB vises are running $250 for ones showing multiple peck track marks from being used on a drill press to $400+ for anything in decent condition. In my opinion shapers are a great addition to a home shop if you've got the spare cash and room, but there only a handy addition to already having a decent mill. And yeah there slow, but that's off set with being able to run without attention on larger parts and fed with a lifetimes supply of high speed steel for the price of a couple of decent larger end mills.