I've got the Cyber WiFi. It is VERY flaky, difficult to setup, etc. I found the WiFi setup to be primitive compared to other household devices that can join WiFi. On my iPhone/iPad, I had to install Google Chrome, as it doesn't refresh under Safari very well. It finally died over the weekend at < 2 years old. Warrantee is 1 year, but my AMEX card adds another year, so I'm OK. Yes, you would need to have WiFi coverage at your egg for this to add any value.
Note that when it worked, it worked well :-)
My dad and some work buddies all have the DigIQ and love them. Once I settle the warrantee claim, I'll "downgrade" to that model.
I would vote XL and a sink. I use the sink all the time and the XL, along with the Ceramic grill Works 2-tier grill, allows for a ton of surface area. Charcoal isn't expensive, and the egg does shut off and sve leftover, so I dont mind using it for a smaller dinner.
We are a family of four, but love leftovers. Why do 1 chicken, when the grill holds 3 or 4 and the refrigerate so well?