The assitance system on the ZTs is pretty reliable, and, if it ever breaks, then some new torsion bars are just an e-mail away. the knives are very easy to disassemble and assemble, so putting in the new torsion bars is pretty easy. as far as preparing food with the 0300 series, the blade is abit thick to be a slicer, but i bet it will cut food just fine if necessary. as far as sharpening, I think that if you are willing to spend 250 bucks on a knife, then a spyderco sharpmaker for 50 would be a good investment to keep the 250 dollar knife is top working condition.
If you are willing to spend 400 on a lionsteel, then i think you might be interested in a sebenza. they are very solid, extremely well built knives with tolerances that are beyond belief. they can totally take abuse, or so i have heard, but they may not be up to the standard of the 0300 series, i don't know. they are both out of my price range. I do own the less chunky brother, the 0200. I think the world of it, not to mention the fact i am carrying it right now, so take that for what it is worth.
tldr, ZT 0300 series, :thumbup: ZT 0200 :thumbup: Sebenza?