The Spectre is a very high quality production knife- one of Gerber's best. 154cm is a US equivilent to ATS34; the differences are negligible. 154cm and ATS34 are excellent steels for knives; to my knowledge, no one who goes to the trouble of making it makes it poorly. (Anyone can make 420,440, and even AUS8. I've had crappy blades made from all of them.)
The spectre is very comfortable in the hand, and I agree the blade geometry is superb. TI-NI is a coating that a) cuts down on corrosion (stainless steels DO rust) and b) reduces friction during cutting- making it easier to cut deeper/longer etc.
The Gerber Walker is also an excellent knife made with ATS34. I find it less comfortable for prolonged use; I also find it stiff to open. I love it though- very good quality knife.
I work retail, and most of what I do is open product/cardboard, plastic wrap etc. For my use, I never buy serrated blades. If you are going to be using a folder for hard use, I'd recommend the Spectre.
Best wishes!
Bill