Have not tried confi dry so there's no informed comment I can make in regard to them.
As for north shore...I wear north shore supreme as my every night diaper except when I am traveling. When away from home I use north shore megamax.
For me there's a couple of reasons. (1) the mega max tapes are very strong. They do not "pop loose". With the supremes I add a piece of tape over each factory tape to hold securely. (Note: I like my diaper tight, I also do not lower or remove my diaper once on, it comes off in the morning. I don't worry about using the reusable tabs) Because I uses tape over the tabs this is extra noise that sometimes is hard to conceal. If I am in a hotel it doesn't matter but staying at friends or family the strong tape with no helper makes a quieter install. (2) the mega max seems like it is able to absorb more which is just an extra piece of mind kinda deal when I am in someone else's bedding.
I will note it seems as though the megamax is a "larger" diaper, so some experimentation may be in order to get the sizing correct. For me I am on the small end of the sizing for the large size supremes, where the medium size supreme is just a touch to small. The mega max is the opposite large is to big for me (leaked when tried couldn't get a good seal where my cheeks meet my thighs in the rear) but the medium fits real well.
The megamax is a more costly per piece diaper over the supreme. This is another reason for me why I use the supremes every day and the mega max when I think its required.
As was said above what works for one person both in absorbance and sizing may not work for another. For me (i would imagine others also) some of this is trial and error until you find the product that works best for you.