So nice! I hope I can get my hands on the Fields of Glory book somehow and start trying it out!
 I have the core rule book for FOG and it is a very different system to WFB and WAB as well .  Tried it out last week with my regular  player using 15mm ancients . 
Very detailed system , using several phases and a joint player action phase . The game is very DBM if you are familar with that system with new rules built in . The lists are avaliable from Ancients to the late Medieval period with the 'Storm of Arrows '  army list as the current release .
I like to do the Italian Condotta merc lists using my DOW army since the Perry Mins they designed for the army book in '98 would be perfect . The scales are for any sized minis but in 28mm the base sizes are a bit difficult for the movement scales suggested . 
But it says if both players use the same 28mm they can ignore the basing rules and play as is . The FOG rules are very challenging and something new to learn . 
I would recommend them if your are a military history nut like me , but it is not for the casual WFB gamer who likes a quick fast game . These rules can   'run the course in time and patience ' in comparison to WFB .