I have all three. I have not played them back-to-back and with the same string set-up and tension. However, it is something I am planning on doing sometime soon. From memory though, the PB10 Mid and the Phantom Pro 93P 18x20 play more like a 95sq in racquet, while the IG Mid will feel smaller (as it is). I can play with all of them, but the concentration will need to be even sharper with the IG Mid.
The other thing that is different is the balance of the racquet (from memory)... the IG Mid being the least HL... although the IG Mids I had a hit with were already leaded-up, and the one I have now is a Pro Stock with Lead under the grommets and Silicone in the handle (it will be an absolute beast of a racquet - I have not had a chance to hit with it due to a double hernia repair). I'm not sure my experience of this racquet would be useful as I never played it stock... all examples I used were already modified in a way that was difficult to alter. Having said that I found the racquet very comfortable, very precise, maneuverable, and great with direction control.
I had to add weight in the head of my PB10 Mid so I could feel the head of the racquet better in space (if that makes sense). I was playing it with other 95-98sq in racquets side-by-side and finding that I swung for everything really early as the racquet comes through the ball so quickly. It is something that would not be a problem if I used the PB10 Mid as my sole racquet as I would adjust. The racquet is very comfortable and plush, it is great on return-of-serve, serving, and groundstrokes, and has a fair amount of power for a Midsize racquet.
The Phantom Pro 93P 18x20 I was able to hit all my shots with from the get-go and I was happy with the balance, however, I felt the racquet could be enhanced with respect to stability and power by the addition of a small amount of weight in the head (which I then counter-balanced with weight at 7" above the butt cap - in order to keep the original balance). I also strung it with Hyper-G 18 gauge (1.15mm) @ 48M/45C, which was either too firm and needed some loosening (as it got better after a time), or was not the right string for me with this racquet. I shall try some softer strings in the future at a slightly lower tension (maybe 45M/42C). The racquet feels firmer than the RA indicates, IMO, but is still comfortable. I love the racquet overall and I will definitely be keeping it.
I'm looking forward to playing them side-by-side (together with my TXP Pro, i.Prestige Mid, and Prestige Tour 600).
Hope this helped.