Chess Tactics Server

I've used the Chess Tactics Server enough now to make a few observations.

Pros:

• Problems are all "real life" in the sense of looking like normal game positions. The device of having your "opponent" (the server) make its move before you helps underline this impression.
• The wide range of different problem types also assists in providing an over-the-board type challenge to the player. They range from simple recaptures to material gain to checkmate, so you need to actively figure out what the position requires, rather than programming your brain for a single type of solution.
• Statistics and records are useful when revisiting failed problems.

Cons:

• The timed rating feature encourages quick moves without checking multiple lines, in a very Pavlovian fashion.
• The rating change indicator for each problem appears to be incorrect, as a ratings penalty always seems to be assessed if the solution is not found in the first few seconds.
• Alternate solutions are not recognized. This affects only a small minority of problems, but is still occasionally annoying.

Some common advice is to do at least 15 minutes of tactics problems like this a day, in order to keep the mind sharp and expose you repeatedly to key tactical concepts and patterns.  I think that's about right for me, any more than that in one session and it tends to become more like rote exercises, rather than my intention of training for serious play.  It's also important for me to keep a tournament game mentality to the extent possible, rather than simply blitzing moves out without checking for blunders or alternatives.  As long as I don't really care about the CTS rating, then the server actually works pretty well for this.