I have both. I prefer the sharpmaker, but the lansky is better for reprofiling edges. Although the sharpmaker is no slouch with the diamond rods, it takes longer. Less fiddly though.
If you could only have one? Sharpmaker.
Spyderco : Resilience, Tenacious, Persistence, Manix 2 G10, Para 3 G10, Para 3 LW, Paramilitary 2,
BBS Paramilitary 2, Amalgam
Kershaw : Tone, Cryo, Cryo 2, Thermite, Atmos, Natrix 7007cf, Natrix 7008cf, Bareknuckle 7777, Bareknuckle 20cv, Concierge
Zero Tolerance : 0566CF, 0770CF, 0770GRYBW, 0562CF, 0470, 0456CF, 0095BW, 0801TI
Ontario : Rat 1
CRKT : Caligo
Civivi : Plethiros, Baklash
Cold Steel : AD10
Benchmade : 810-1401 Contego
Buck : 110, Bucklite 422