We tried the 1870 Rules over two nights and whereas there is plenty to recommend them I have to say we did get a bit bogged down in some of the micromanagment aspects of the rules. They are stated to be Grand Tactical which indeed they start off as but we found that there were aspects which were vague and we would have to introduce a number of house rules to cope with.
However there are many aspects which I loved. The firepower rules are a little clumsy but once mastered they work quite well. The French rifles are very powerful and cavalry is quite impotent in the face of steady infantry but the artillery – even massed Prussian batteries – were not quite as decisive as I imagined they should be. On the other hand the Jaegers and Chasseurs were very effective.
Overall I think these rules are very good but there are a large number of errata and amendments on the website which make it very hard to read the rules through.