I bought the Excaliber clock a number of years ago, and I have no complaints. There are many settings, and it's pretty straightforward how to select them. There are many (maybe 50?) quick pre-set times listed on the bottom of the clock itself (so you'll never lose it). Just select the corresponding number and you're ready to go. I don't know about the ease of the Saitek clock... like most clocks you don't know how to program yourself, when you see someone set it, it looks terribly complicated (although I'm sure it's not hard once you know how ;)
I've seen the Saitek at tournaments probably just as often, and it's also a good clock.
To me the main difference is the appearance/feel of the clock. The Saitek clock reminds me of a brick. It's solid and square... so to me it's not very exciting :p
I like the look and feel of the Excaliber clock better, although because the plungers are fitted a bit loosely, it gives the impression that if you let kids play blitz with it (slamming the clock every time) it may eventually break.
You can see the circular buttons on the picture are maybe an inch or so across? Well that entire surface area isn't connected to the base of the clock, it's more a mushroom shape if you got down to table level and looked right at it. With the Seitek clock that entire rectangle is attached.
I need to get a chess clock I have been looking at the Excallibur Game Timer II and the Saitek Competition Pro III.
If you have experience with either of these clocks, good or bad, please help me out. The price being under $50 is important. I would also consider any clock in that price range if you feel it is a better option.