Just be aware that the cadence on both of those is wired. Not a bad thing but you will have to run a wire from the head unit down back to the chain stay. If you are going to do that the Cateye Astrale is a good one for around $35. The speed is wired to but they both mount on the chainstay so if you are on a trainer everything still works. I have the Sigma BC 1606L DTS wireless with cadence. The cadence is also wireless and you can mount the speed sensor on the rear seatstay and still get a good signal to the head unit. I paid $80 for mine and really have been happy with it. Lots of features including a backlight.
Madone 5.0, Old Trek 412, Shogun 1500, Diamondback Topanga frame (Warranty replacement of broken Raleigh)
I currently have an old Cateye CC-6000_E Micro I will keep on the current bike. It has the Cadence and speed off the rear wheel. The mount also positions the unit over the stem for those symetrical people.
I like the Sigma but does is have more than 2 lines of Data? If only two lines will it show speed and cadence at the same time. I had a Cateye Solar at one time that would show speed and cadence at the same time. It is like a tach and speedo on the motorcyle. I can see how fast I can push in a given gear.
Fuji Team Issue, GT tandem, Couture (bet you never heard of this one)
It's what I use on my road bike and it works fine. I got mine from Performance for $29 so it was hard to go wrong. I like the multiple lines of information so I don't have to scroll.
I use a Cateye Cd300dw on my TT bike and I've had intermittent signal problems with it and it tends to lock up when I hit 120 rpm spun out with a strong tail wind (common on the monthly TT course around here). Very annoying and I've never had this happen with the wired $100 less db 4LW-C. Go figure.