If I had the time to play live, I'd play live every single time. However because time is scarce I play online.
My local casino was only spreading 5-10 Limit poker and higher until recently when they finally adopted 1-2 NL so I'd much rather go there and play that versus playing online. However, the casino is 30 mins away, they generally only spread one table off-peak and the wait list is usually pretty long. So as much as it pains me I play online as my poison of choice.
Online
tells are a plenty just like they are in a live environment, you need to do your research on your opponents and recognizing what those tells are, but online they are out there as much as they are live.