Well guides can be both good an bad. Sadly my experience is that it's mostly bad because people watch them then stick to exactly what they saw in the guides.

My group always goes in blind and learns and understands the fight to as far as we can go(this seems to confuse some people though).
If we are hitting a wall after that we will check a guide or two or ask our LSs for tips - if we clear we might check a guide to see if there is anything we might improve.

It's the understanding of what a mechanic does that means you can always adapt to the fight and not expect the fight to conform to you and your startegy.

And yes it takes hours and hours of wipes at times to master the mechanics to the point of actually getting through.