The germination problems are over...I think. I got two packs of Haze special last march for an outdoors run, out of 20 I had 17 pop and the last three were my fault as I had a less than ideal germing setup at the time (a dinner plate, some soggy rockwool and an upturned cooking pot over top of a vent). If the seedbank your buying from is reputable then I'd say go for it.
As for potency, I had to harvest my hazes about 20-30 days early because of weather. They really aren't appropriate for my area (42 * N in NA) but some of them did turn a very dark purple. I have a bunch of really old school scraggly looking "purple haze" now and it is a remarkably strong sativa effect for such immature bud. The purple is more on the dreamy side of sativa, the green/yellow stuff is all up, up, peppery thai high. Fresh it smelled very strongly of Frankensense (the ehtiopian restaurant smell) and cured it smells of sandalwood, pepper, pathchouli, anise and other sweet/savoury/spicy herbs.
Im going to run his k.c 33 next year for sure, it should finish in time for me here (hopefully..)