My apologies if this topic has been addressed before.

How close, performance-wise, is a sharpened Albion Squire Line sword to the Albion Next Generation swords? I'm not concerned with fit and finish, simply blade characteristics.

Thanks in advance for any insight!

Have you checked out this: http://www.myArmoury.com/review_alb_13th.html

In that review, I compared the cutting ability of two Albion Type XIIa swords, one a NG, the other a sharpened SL, on soft targets like pool noodles. The cutting on those targets was very similar between the two.