I have one, a Bridgeport E head. 4" stroke; 1/3 HP motor. I bought it about 14 years ago and used it three times. As far as Im concerned it paid for itself. It cannot be beat for tapered splines as in steering arms. I re-tooled a shaft and steering arm off an old - road grader, I think. Parts were unobtainable and without steering the machine was useless. With the shaper head and a rotary table I could re-tool the splines on the welded up shaft and arm so they went back together in their old relationship. I didn't make much money at the time but I got invited to a lot of the customer's family dinners and cook-outs. I dated his older daughter for a couple years.
OK. To practical matters, the BP shaper head isn't very robust in terms of stock removal but because of a turret mill's large range of axis travels detailed shaper work can be performed on large parts. Very handy, if and when you need it but, remember, it makes onl little chips.
A purpose-made shaper is a more robust machine. I refer to serious shapers not the SB or Atlas 7" home shop variety. Not to say they aren't a real asset for very small parts and work for which low stock removal rates don't pose a problem. These small shapers quickly get frustrating come time to cut keyways where their limited thrust and lack of rigidity interferes with progress and they don;t really take up that much more shop floor compared to an Atlas on a homemade wood stand..Larger than 14" and, yes, they get bulky quick..
If you want to get serious, find a 12" to 16" shaper equipped with a universal work block and a purpose-made shaper vise..Such a machine, if good condition, allows you to re-tool the bed ways and cross-slide ways on the saddle and the cross slide and compound ways as well for smaller lathes. Also it will have the beef to reproduce Aloris type tool posts and holders and tool holding accessories.
A shaper is a good machine in its niche, and, in the right hands, it can be very productive but, sadly for general rectangular work, even a turret mill will out-perform it.
