is this kit any good

[wiatroda]

Sounds good for me.
I'm using the same Breakout board and steppers in my CNC. Instead of PM542 drivers I have PM752, hence higher supply voltage.
With my setup I'm able to mill steel, and I would try the same with your set. Eventually in case of loosing steps or motor stalling I would decreased Feed rate.
But If you want to buy pieces separately I would recommend PM752 - http://www.slidesandballscrews.com/p...ml?cPath=44_97
and some handsome 500W toroidal transformer (eg from Farnell- free delivery on orders above £20+VAT) + 25A rectifier bridge + big capacitor (voltage not smaller than DC after rectification).
for reference: