I went straight from playing Wilson Tour Staff FG-17s (2i-pw) to my current Nike Ignites. I have played the blades since I started 5 years ago, but only started playing a lot this year.
The blades were, honestly, a lesson in tough love. I learned golf under the premise that if I did something the least bit wrong, I was going to pay a horrible, horrible price. The tradeoff was that I really felt good when I hit a good shot, and I could do a good job of diagnosing what I'd done wrong if I screwed up. As has been said, I could tell you where the ball went without looking.
The Ignites, by contrast, feel the same no matter how you hit em. That took a while to get used to. It doesn't bug me now, though.
The difference is that I've developed the confidence with the Ignites to play something that more closely resembles golf. Before, if I had a sand trap in front of the pin, I'd always aim left or right and play safe, because I didn't have a great chance of getting over. Now I actually think about the shot, what I need, and what I can accomplish. The first time that I had the guts to go for a green, over the water, 160 yards out, was fantastic.
With practice and equipment changes, I've gone from the 120s to the 100s this year. I'd estemate that about 5-8 strokes have come off because of the Ignites. However, after reading this thread, I'm really tempted to pull out the old blades and see if I'm man enough to hit a 2 iron blade out of the rough.
EDIT: One more thing I miss on the blades - the thin line at set-up. Took me forever to realize that shots with the Nike clubs didn't line up by themselves like they did with the Wilsons.