Pros are the bike handles more quickly, requires less effort to turn in and is more lively
cons are that it may become too lively!
You can probably find a great comprimise with a good aftermarket damper like the hyperpro. Short of that, running 2.5wt oil in the stock damper makes a noticeable improvement in handleing without really risking much.
I've been running without the damper for the last 38k miles or so and am quite happy with the way the bike handles. Others have gotten seriously hurt from crashing after headshake with and without a damper- I've never gotten the TLS to headshake, but then I just ride street. I imagine that if I were riding trac on the TLS I'd probably want a damper for the added security, but at even semi-legal speeds headshake just isn't a problem on the TLS for me. I have spent a lot of time racing MX bikes which are drastically more prone to headshake than the TL and may have a somewhat different prespective than most street-only guys.