I wish there heads had been available a few years ago.
Actually we are having problems getting them in the UK. 440m Source have ignored some orders from the UK and when contacted have stated "we want all the stock for the domestic market".
So far, apart from what has been said here I have only heard that;
The seat to head transition is not great, minor clean up required.
The fire ring on a head gasket can overhang the chamber, ROL gaskets seem to offer the best fit.
The as supplied springs are not great, factor in the cost of a set of springs for solid lifter cams. But you should match the springs with the cam anyway.