To add a little information to this post...
The Apple Lisa uses tall KetTronic Foam & Foil switches, the Compaq Portable (original) uses the short variety. Both are linear with the coil springs. The Lisa was introduced to the market in 1983, the same year as the Compaq. However, the Lisa started development much earlier, so I think that explains its older switch design.
Short switches designed for the coil spring have a little ridge to keep the spring in place, here's the Compaq (the keycaps are from a later Unisys branded KT board)

- IMG_1390.JPG (192.82 KiB) Viewed 7018 times
The tall switches on the Lisa keyboard don't need a ridge for the spring to sit in. Note they're marked KeyTronic Spokane.

- tall_sliders.JPG (153.63 KiB) Viewed 7018 times
The Dell Enhanced Keyboard is a rebranded KeyTronic "Professional Series" KB101. I have one from 1988. I also have a KeyTronic branded KB101-C with Windows keys, from 1995. The Dell and KT are not quite the same color, the keys on the Dell are a little more tan colored and the green of the double shot Alt key is darker on the Dell.

- Dell_and_KB101-C.JPG (234.45 KiB) Viewed 7018 times
The switch assemblies on the Dell and KT are like the tactile one posted above... 2 little nubs keep the rubber sleeve in place. It is possible to swap the rubber sleeves out for springs to make the board completely linear, but the rubber domes can't be fitted to a board designed for springs. Something about the slider mechanism gets in the way and the keys stick when fully depressed.
Here's a comparison of the tall and short springs. The shorties are ~13mm uncompressed, the tall ones are almost 2cm.

- Short-Spring.JPG (125.95 KiB) Viewed 7018 times

- Tall Spring.JPG (137.24 KiB) Viewed 7018 times

- Rubber sleeve.JPG (112.85 KiB) Viewed 7018 times
And here are the keycaps: Lisa, Compaq, Dell, KB101-C. Notice how much taller the Lisa ones are. All are double shot.

- Keycap_front.JPG (175.37 KiB) Viewed 7018 times

- Keycap_height.JPG (99.79 KiB) Viewed 7018 times
The shorter sliders, caps, and springs make a huge difference in the height of the keyboard. The Lisa's space bar is just over 6cm from the desk, the newer boards are 2.5cm.

- Lisa-Height.JPG (149.31 KiB) Viewed 7018 times

- KB101-Height.JPG (227.54 KiB) Viewed 7018 times
I owned a couple DEC VT100s in the past, their keyboards are about the same height off the desk a a Lisa keyboard. So the advert above touting the new low profile board makes sense.
PS: I had to rebuild the switch assemblies in the Lisa, Compaq, and Dell keyboards. What a colossal pain! The KB101-C worked OK out of the box (something I was hoping for with the Dell), so hopefully I can get lots of use out of it before it needs attention. Yes, I'm daily driving KT Foam & Foil boards, I like the lightness of the switches and solid feel of the boards (they don't flex at all, and the little bit of case creak is easily fixed with some fabric backed tape on the case seam). I greased the sliders on the Dell, it makes the whole board super quite to use. Probably the quietest board I've ever had, excluding one of those horrible flexible boards.
I got the KB101-C as new old stock, and I'm unsure if I'll grease the sliders on it yet. Kind of neat having a "vintage" keyboard that's not even worn in yet!
Thanks,
-Jason