[mattak]

Most multitabling players can maintain full focus up to about 4 tables or so then the attention to detail goes down a bit. No one will argue that the more tables you play the less your focus on tells and betting patterns.

The reason people multi table is that if you are a winning player on one table at a certain winrate, you can double your hourly income by playing two tables, triple by playing 3 etc. Even if your winrate slips a little on each individual table you still are ahead on your hourly rate.

eg.

player is beating 100NL for 5BB/100 hands on one table. He is making $5 per hour.

if the players starts playing 4 tables his win rate goes down to 3BB/100 hands because of lack of focus etc. He is now making $12 per hour.

In the end, what is more important? Pretty easy decision imo.