Has anybody used the above? Thinking of ordering them and i'm wondering how they compare to Black powder? I'll be wargaming 1859/66/70 with them. 

I haven't played these but I do own them, have read them and have played all of his other rule sets (which they resemble in many ways).  They are simpler than Black Powder in every particular.  The basic philosophy for all of his sets is to make them as simple as possible with some sharp (exaggerated?) period chrome.  One way of this simplifying is his use of relatively small units in relatively small numbers. He even has scenarios specifically designed for 2'x2' boards. The design philosophy of black powder on the other hand is to allow as big a game as possible (large numbers of units, with large numbers of troops in each) but still have it very playable.  Black Powder is all about the Warmaster-type command roll and the characteristics which make each unit.  Neil Thomas only adds in command rules in as an optional extra, preferring to keep the rules more simple and letting the dynamic of the game create the tension and the mistakes.

Im interested in this too. How is basing handled if you use the 60x30mm Basing ?

Two options: use 4 60mm x 30mm bases per infantry and cavalry unit and 2 60mm x 30mm bases per skirmisher unit; or use 1 base per unit and have some way (markers/roster) to mark hits.  I have done both (for other versions of his rules) and both worked fine.  The first is like playing with 25/28mm figures (but looking better!), the second allows you to play good games very cheaply on a very small board indeed.

Thanks for the answers. I bought the book and it is very light rules-wise but the author does defend his reasonings in a good manner. I am probably going to try Big Bloody Battles and then i'll have to pick as im buying more rule books than reference books!