I use both: I have a Park PRS-4W
u-bolted to one of the jack posts in the basement. Probably the most stable stand I have ever used, but not very portable. I also own a Tacx Cycle Spider Team
, which is the workstand that prompted Park to create the PRS-20 and, ATMO, is still a better design. That's the one that goes on the road and is a secondary stand for group wrenching in the man-cave.
Park's traditional, cast Adjustable Linkage Clamp is fast and convenient, but unless it's attached to those big-ass cast iron floor plates, or bolted to a wall, post or bench, it doesn't provide a whole lot of stability for loosening seriously stuck parts (like frozen-in bottom brackets). Even the old PRS-5 couldn't hold a candle stability-wise to those euro stands that held the dropouts and the bottom bracket shell.
As far as difficulty cabling bikes in a beam-type stand, I haven't noticed it. YMMV, of course. And as far as not being able to work ont the front brake on these stands, that's why they usually feature a second clamp for the rear dropouts, so you can flip the bike around, reinstall the front wheel, and get back to business.
IIRC, sawhorse/beam-type stands evovled from the race-mechanic tradition of taking both wheels off the bike, throwing the frame on the stand, thoroughly washing the bike, inspecting, lubing, and replacing what is needed, doing the wheels separately, and reinstalling the wheels when the bike is on the ground before moving on to the next bike. These stands provide 360-degree access and enough stability for torquing on BB's if needed. Might take a few more seconds to get the bike on and off, but many mechanics who use these stands day-in and day-out would gladly trade that for more stability.