Lockup is rock solid on the one I EDC and on the other two I used to have. Im OCD just like you... or worse. I post a comment whenever I buy any knife from a company or dealer online: Please inspect my knife for blade centering, must be perfect and stay perfect after being opened and closed a few times. Also check for lockup, make sure there is no blade play. Ive had 3 350s and one came out of the box with an off center blade, I didnt want to mess with it so I sent it back. The next one came perfectly centered, but drifted off center within a few days. I took that one apart and did a little trick I found on the forums and recentered it. It stayed centered so I kept it for a while before trading it off to make room for my 350SW, stonewashed version. I would recommend this knife to anyone, but I would also suggest that you either buy it from an honest person on the forums who will send you pictures of the blade on center. OR I would suggest buying it from a good online shop and ask them to inspect the knife before shipping it like I do. The places I have purchased through and requested the inspection, and did infact inspect my knife, were BladeHQ, Knife-Works, and throught Kershaw Guy. They all have great prices. Even SOME of the ebay dealers will be honest with you and inspect the knife, just make it clear that you "wouldnt want to have to send it back for a refund and buy somewhere else". Ive had one experience where I messaged the seller and asked about the centering of the knife I had just paid for,asking him to inspect it, and he was very nice and replied that he only has two in stock and both are a bit off center, one is barely noticeable. So he asked if I wanted the one with the closest centering or if I wanted to cancel the buy, with no consequences or bad feedback of any kind, I opted to cancel... he sent me my money within minutes. And now he is one of my favorite sellers on the Bay.
Wow this is a bit more than I was thinking I would type. lol. Well bottom line is the ZT 350 is an amazing knife and you should buy one if youre thinking about it. Blade centering would be the only thing I would worry about so just buy one from a BF brother who can show you how centered it is.. Or buy from a good online store like BladeHQ and ask for an inspection before shipping. I would highly recommend KershawGuy, he is a great person to deal with and will inspect your knife upon request. And he has great prices.
Good Luck