As far as space, one of those HF lift tables is nice because you can just park the bike on it where it sits on the floor, so you're not really losing any space.
Yes, you can't beat the HF table lift, with a few mods (grind the sharp corners off). We just discussed these in a recent thread and the consensus is the older ones were made better. So, if you're not in a hurry, shop for an older used one.
As far as floor jacks go, I prefer the screw type over the hydraulic ones. They are more compact and more adjustable.
Is there a good way to tell the difference between the new one vs old one by looking at them? I plan on picking one of these up eventually, but I'm not now sure what the difference is between new vs old?
I also have one of those flat motorcycle scissor lifts. I just used it this weekend for the first time and it made the job amazingly easier. I could've used a normal floor jack, but just like you said, it would've been a giant hassle to try and get things lined up properly. I had to replace the front rubber isolator mount on a bike with a hanging engine, and I was able to put the lift under it, take pressure off the engine mount to easily remove the hardware, then drop the front of the engine down an inch or so to get to the hardware to replace the mount, then lift it back up to the perfect height for the bolt to slip in without any resistance. Would've been practically impossible with a hydraulic jack. I just bought one of the Chinese versions on ebay. I won't kid myself with trusting the 1100lb weight limit, but for projects where you're just supporting an engine or lifting the front or rear of a bike while the other side is on a stand, it seems pretty decent for the money.
Aside from that, I have a lift similar to what mailman has above. Very convenient when it comes to being able to move the bike around the garage. Otherwise you pull the wheels off of a bike and it's pretty much stuck in place until you get it back to where it way.
I also always park my bike on rear stands(or a center stand if you have one) when the bike is at home. I had a sidestand bolt break once, which resulted in the bike flopping onto it's side on the ground. Luckily it was only a supermoto, so all you have to do is chuckle and pick it back up, but that's a lot more painful on other bikes that are easily damaged. Because of things like that I try to keep them off of the sidestand as much as possible, even if I'm not working on the bike.