To be honest, I like the old style wooden/pastic ones like this:

http://www.walmart.ca/en/ip/north-st.../6000002585561

I've never had much luck with the pressure mounted ones with the gate, I tried one but it was quite heavy and not super sturdy - I was worried it would fall on the kids if they pulled. These ones are super light, so even if it did come off it wouldn't do much damage, and they're the easiest to get on/off. Not great if you want something permanent, but it works great for me!