Rosebud: The summer video monitors are great. I'm always confused by the Amazon reviews because they are never that great for Summer, but we have three of them (2 the same model, and then 1 a different model), and we like them. We have wifi and cordless phones and have no issues. Our first one is barely working (the sound is awful and it won't work without being plugged in, but the picture is still fine) after 3 years, but it's been dropped and thrown about 1,000 times so I think it's amazing that it's even still working!
I think they are the best one for the price since they aren't very expensive. I think you can get them on Amazon for under $130. Even for $140 you can get the one that zooms and rotates (we don't have that one) or the one where you can talk to the child (my friend has that one and loves it). I'm sure there are better ones though if you want to spend more money.