Opinions about the lenses supplied with 2x3 Graphics, e.g., the Century, are mixed.
Ranked in order of price, 105/3.7 Ektar > 101/4.5 Ektar > 101/4.5 Optar > the triplets.
Chris Perez' lens tests found the 101/4.5 Ektar sharper across the field than the 105/3.7 Ektar from f/8 down; this is consistent with my shooting and formal lens tests, but I didn't get near the lp/mm resolved that Chris reported. Subject to a retest, my 103/4.5 Graftar is better than both of my Ektars at f/16 and f/22 across the field; no results at larger apertures, sorry.
I've never shot any Xenar, expect the 105/3.5 to be no better than the 101/4.5 Ektar. But if you want to know whether yours is better than your 101 Graflar, ask the question yourself. You have the lenses. And compare both with y'r 105/3.7 Ektar too.
The 100/3.5 and 105/3.7 Ektars are slightly cult lenses. Cultists say that they render out of focus areas and the transition from in good focus to not in good focus especially well. I've never seen it, but I'm an ignorant barbarian and am blind to these fine points of lens performance.
Good luck, have fun,
Dan