There are pluses and minuses for each. The Lansky hones are narrower, which is never good in terms of total surface area (therefore working speed). Also a little prone to tipping, as their taller height also makes it easier to push them over, if not careful. On the other hand, the narrowness of the Lansky hones is a little easier to deal with on recurves or on very small blades (such as pen blade in traditional pocketknives). The Lansky system (as a whole) is more user-friendly to smaller blades, as the clamp and guide rods will still allow the hones to reach the edge at lower angles. That's the biggest drawback of the DMT Aligner's clamp; doesn't easily handle smaller or narrower blades without some sort of improvisation.
In terms of the abrasive quality of the hones themselves, I like the DMT;s 'mono-crystalline' diamond better than Lansky's (likely 'polycrystalline') diamond. The DMTs seem to work a bit faster, and the diamond seems more uniform in size & distribution, which translates into a more uniform finish in the end.
To some extent, you can utilize the individual advantages of Lansky's clamp together with DMT's hones, in one setup as seen below (Lansky clamp shown in use with DMT Dia-Fold & Magna-Guide):
David
