This definitely falls under the category of personal taste, and it is just that, personal.
Anyway, I own a Starmate and have handled a Lum and carried a buddy's Lum for a few days and here are my observations: First, the Starmate is an awesome general purpose knife, it will do most anything required from opening boxes to cutting frozen chicken with ease. The CPM440V blade really does keep a keen edge for longer than a comparable ATS34 blade, at least in my opinion when compared to a ATS34 Spyderco Military I have knocking around. Second, the ergonomics not only look pretty interesting, the knife really fits my hand. Other's mileage may vary, but the handle really sticks to my palm and is comfortable to use for extended cutting sessions. Third, after four months of HARD use and a few resharpenings, my Starmate looks new.
As for the Lum, didn't care of the handle shape much. The steel is ATS55, pretty sure, and was never as sharp as the Starmate. The one I handled in the shop didn't lock securely. My buddies did, but only after a week of breaking it in. He carries it daily and the titanium scales look like hell or maybe he is just hard on the knife. Cutting performance is not on the same plan as the Starmate. Blade profile looks awesome, but leaves much to average cutting utility.
Bottom line, Starmate is the best Spyderco to date in my opinion and more knife than the Lum. BUT get out and handle both yourself. Personal taste.
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"Women bring life into the world
and much death, for they sway the
destinies of men." -Anneas
[This message has been edited by chrisJohn (edited 28 November 1999).]