I finally made the move from the YTs to the IGs. I've had the IGs in my closet since last summer. I have been using the YTs for quite some time but they are on the edge of elbow pain for me. If I play too much, then I have to rest my arm for a day or two. I don't have that problem with the IGs but my serve wasn't as effective with the IGs because of the higher swingweight.
I had some problems with the YTs (they aren't identical) and I put in some effort into matching them up but was unsuccesful. It can be pretty frustrating trying to match frames up yourself. My IGs are matched - the YTs have different pallets - one is squarish and one is rectangular. I think that the specs were the same: balance, static weight, length - but the swingweights felt different. That happens when you don't buy matched sets.
I played 1.75 sets today and was playing better than I've ever played with the YTs. My opponent said that I was playing "lights out". I modified my service timing to better use the additional swingweight and the racquet just had gobs of power. I think that I need to string it a little tighter - maybe 56 instead of 54 to get a little more control but it feels pretty good where it is.
The best thing is that it doesn't put any stress on my elbow. I had 9 inches of lead at 3/9 (each) on the YTs and still could get arm issues. I have no lead at 3/9 on the IGs and have no arm issues. So I guess I'm a happy camper with the IGs now.
4 x IG Prestige MP, 70 cm, 376 grams, 386 SW, ALU Power @54, Prince Syn Gut 16 @58