My experience with Efke 100 and TOL now amounts to 4 sheets of 11x14 film. I used the XTOL at 1:1 at 68 F. Two sheets were developed (separately) at N and 2 (also separately) at N+1. I developed for 13 min. for N and 16 min. for N+1. My "densitometer" consists of printing the negatives on PMFA with a grade 2 filter, then using the 1 deg. spot meter on reflected light from the print.
Both "N" negatives fit my expectations for N development, while N+1 slightly exceeded both my standards and my expectations.
Grain was very slightly smaller using the 1:1 XTOL than HC110 B. on 4 identical negatives. Acutance was a little better with XTOL than HC110, but visible only with the 5X loupe. The contact prints were identical to inspection with the naked eye.
Additionally, the XTOL smells better than the HC110.
Downsides: Price--XTOL is more expensive. 5 liters is advertised to develop only 8 11x14 negatives [320 sq. in./qt at full strength. 1600 sq. in./5 qts.] at full strength or 16 at 1:1.
Ease: Mixing two solids is more difficult than 1 syrup.
Volume: Who owns a 5 liter container? I mixed XTOL at double strength for a stock solution, and then mixed 1:3 for a 1:1 solution.
Shelf life: 2 months for XTOL, 6 months for HC110.
Given the modest improvements in grain, acutance, and expansion versus the many downsides, I would not recommend XTOL for 8x10 or larger with Efke 100.
I will stick with HC110 for now.
Next comparison: HC110 vs Microdol X. Coming to an APUG forum near you!