Well its taken 20 odd years for me to do it, but I've finally tasted Advanced Squad Leader with Starter Kit 2. Up till now I'd be put off by the fact that ASL seemed to me to be more a way of life than a game, but the scale of the starter kits (and the fact that I only needed one to use the Brits) was all the encouragement I needed.
So far I've only read the infantry rules needed for the first two scenarios included and played through these solo to get the hang of the rules before playing against a live opponent. There are a couple of things that are very different, the defensive fire rules, though in SL it was possible to use tracking to fire against an opponent while they were moving it was not resolved immediately like the current rules. The possibility of using subsequent fire as well makes the defender more effective and really creates an incentive for attacking forces to spread out and minimise the possible damage from any attacks.
Apart from this the handling of rallying and troop quality is a change, with the steady erosion of quality and unit strength that can occur from morale checks has increased the penalties for these. On the whole the changes emphasise the need for force conservation by a side and this is realistic.
So far I've not found it overly complex and I look forward to playing this more regularly now. Probably adding the other two starter kits, but I'm not sure I'll look at making the investment of buying the full rules and associated supplements needed to play ASL in the round.