Question about different types of clubs and fittings.

I'll try to keep this short.

I have a set of Titleist 735 CM's I got off eBay. Regular loft and lie, I believe, and regular or possibly stiff shafts. Today, I hit my friend's Burner 2.0's with senior flex graphite shafts and a more horizontal lie angle. These two sets are night and day different, and I hit my friends night and day better than I hit mine. I got the CM's with the intent of getting better and growing into them, and I have already started to do so, to some extent. But holy cow, I hit the Burner's so far and high - the ball just kept going, a very strong ball flight too.

My biggest question is why? Why are those clubs so drastically easier to hit than the likes of mine? Money is an object, but now I'm determined to go get the funds together to get properly fitted for a new set similar to the Burner's I hit today. I like this game way too much to not make an investment like that which would allow me to enjoy the game even more.

The Titleist 735 CM are "Players Clubs" - forged irons with minimal offset, minimal cavity and 9 & PW are muscle backs. Those clubs are aimed at single digit handicaps. The Burner 2.0 are "game improvement" irons and have more offset, big cavity, lots of perimeter weighting, lower center of gravity, etc.. to make them easier to hit.

The shaft also has a lot to do with it. Check your shaft bands - if they say R300 they are regular flex, S300 are stiff flex. If you are trying to play a stiff shaft when you need a regular or senior flex you will lose distance and have problems getting the ball up in the air.

Yeah I knew they were player irons. I wanted to "play" myself into them haha. I just went ahead and bought the 2.0's today. I just hit them further, higher, and better. The regular flex shaft helped, but I've swung regular shafts before, and it didn't feel as good as these.

I was actually wondering if someone could explain the physics behind it? What is it that makes the ball fly so much easier with my new clubs?