There used to be a time when it was considered an insult to describe someone as an 'online player'. Now I think it's more of a compliment. You still see a lot of terrible play in slow-clock tournaments from online qualifiers, but in terms of cash play, I think it's a lot tougher to make money online than live.
Here's a hand that I won at the Victoria a few months ago. I wrote down the detail immediately after it happened because I think it so perfectly illustrated the difference.
The game was £100 Pot limit hold'em, with two equal blinds of £3. In this hand nobody posted an optional straddle.
I was in the big blind with JJ.
Two people limped from middle position and the 'small' blind raised £12. I re-raised another £30 and the two limpers folded. The small blind called.
The flop was 442.
The small blind bet £75. I raised another £125 to £200. The small blind called.
The turn was a 4.
The small blind checked and I bet £240 all-in.
He called and announced 'There's no way I'm passing this hand!'.
I showed JJ, he showed TT. I won a pot of £976.
If you've played online cash no-limit hold'em lately you'll know that it's almost impossible to win a pot of 325 big blinds with my hand on that board. If your online opponent were in this spot he would either have a lot less money or he'd only call you on the flop and turn if JJ was losing.
You don't win $1,300 pots with JJ over TT in $2/4 NL hold'em online. Period.