Those all look like good values. I've put Fulcrum on my shopping list for a frame I'm building up over the winter.

Regarding Shimano cup and cone hubs with loose bearings, if you're in an area with enough used bikes for sale, check the ads for good used 1980s-'90s road bikes. In my area it's pretty easy to find good older road bikes for around $200, cheap enough with good components that are often worth more parted out. That's one way to snag a good older wheelset with Shimano 600 or better hubs, dependable low profile rims (usually 32 spoke, you won't find many with fewer or flat bladed aero spokes from that era). The rims are often Wolber or Araya, both very comparable and very good for that era. I have a late 1980s wheelset from a Centurion Ironman, Shimano 600 group, with Shimano 600 hub on a Wolber Alpine rim. Really sweet hub, smooth as butter, better seal design and quality than the Suntour GPX on my other Ironman.

The only catch is these older wheelsets will usually be 7, 8 or 9 speed at most. But I've ridden 5, 7 and 8 speed so long I'm accustomed to it. The main advantage to more cogs is more subtle steps, which is less tiring on hard rides. With only 8 or fewer cogs, invariably there will be at least one shift that feels a bit abrupt or uneven and can add to fatigue over distance with faster group rides, or solo time trials.

However the downside to older Shimano hubs is finding the correct cones. This can be a PITA. Another reason to go for the Shimano 600 or better -- they're a bit easier to find cones to fit.

And when considering used cup and cone with loose bearing hubs, there's a fairly simple trick for quickly checking the condition: Remove the wheels from the bike. It's easier to do this check with the skewers/QRs removed, but that isn't necessary. Twiddle the axle between your thumb and fingers like operating a combination lock dial. Feel for any grit or hesitation. It's pretty rare for actual grit to infiltrate a hub, but that gritty or crunchy feel usually means the cone is pitted. As other folks mentioned, for some reason hubs were often assembled way too tight and if ridden that way the bearings crunch into the hardened but brittle cone race surface. The races are usually fine, they're extremely hard but not brittle. And the bearings may be okay but those are cheap and easy enough to replace. The tricky part is finding replacement cones.

If that sounds like a lot of trouble, it is. Gotta admit, the only reason I bother is because I like older bikes. And I'm a cheapskate.

Those three wheelsets you linked to all look fine. Personally I'd go for the Fulcrum, based on owner reviews and the company's reputation.