I am playing Steel Panthers: World At War and Combat Mission: Beyond Overlord. Originally I played only with AI or PBEM, because TCP/IP was not supported. Then both of these fine games got TCP/IP, and I surely tried it, once. The problems with TCP/IP are obvious:
* All players (two in case of SPWAW and CMBO, up to 16 in case of SE4) have to be on the computer at the same time for several hours without a break.
* What happens when someone disconnects?
* You are forced to wait for other players' turns even if you have nothing to do (in SPWAW or CMBO when someone is attacking and the other defending, usually the attacker has much more things to do than the defender).
While playing TCP/IP was fun, playing PBEM is much more comfortable, and you can actually use your brains. And if you do not know the game well enough, you can study the manual etc. TCP/IP is better for games like Unreal Tournament, where you only need quick reflexes. (Imagine playing UT by PBEM.)
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PBEM