I have a CZ 527 American in .223 and think it's great. I've read your posts about your friend's incident and if it's affected my opinion of the rifle at all, it has reinforced my confidence in one of the few hammer-forged receivers still in production. Some criticize hammer forging as 'old fashioned', but it's the method that produced the best of the firearms and
artillery used to fight both world wars. Those actions not only saw higher power service rounds, they endured terrible abuse, neglect, and repeated cycling/sustained fire no sporting rifle will ever see. I would not feel the same way about an action made extensively of investment cast parts (Ruger, newer Sako & Tikka, Kimber, Montana Rifle, and others), or simply cast mystery-metal or brass with hardware store screws and plastic barrel-bands (Henry). Remingtons are simply drilled from round stock. Winchester CNC mills theirs from block of solid billet.
I understand your shaken confidence and enthusiasm, but I hope you'll look at the situation in a rational way and consider that CZ probably has the fewest stories such as your friends floating around out there, despite being one of the biggest arms manufacturers in the world (although uncommon in America). There's a reason they (and their BRNO ancestors) are favored by professional hunters in Africa; they can be counted on to work safely when they are needed most.
By the way, these are examples of what can happen when rifles that aren't built like your 527 fail:
Notice that none of these pictures (of three separate rifles) show the heat discoloration evident in your friend's blown case and bolt.