metal scanner for logs

I've been researching metal scanners for logs and have found a few prospective models, but I'd like to get some opinions. We normally only saw logs from wooded areas and very rarely hit any metal, but several of the ones at my mill right now are urban or at least cut from someone's yard. I've seen positive comments on here and Amazon for the Cen-Tech, Lumber Wizard III, and Zircon MT6. Mine is an OLD circle mill and does fine cutting lumber for personal use, but this is just a hobby and we only saw 1-2 times a year or whenever we have logs. I'm leaning heavily toward the Cen-Tech model based on price and functionality, but I have to ask - are the other two models sufficiently 'better' than the Cen-Tech given the 2-3x price difference and my use case?

I have a Lumber Wizard. It has worked well for me. It's supposed to work to a depth of six inches. That might be an issue if you are sawing logs. I've only really needed it for thinner material - recycled or found material. Never tried the other brands.

I have a Lumber Wizard 4. I haven't used it enough to rate its performance nor do I have a competing model to compare it to but I have had a very positive experience with the company. I bought a used Wizard 3 on Craigslist that didn't work and when I contacted Billy Carmen at the company he offered to repair it free of charge including return shipping. They haven't made that model for a number of years and didn't have the required replacement part so he advised me that it wasn't repairable and offered to sell me a new Wizard 4 (plus 3 for my friends)at wholesale and threw in two free Little Wizard 2's. Billy is a first class guy and great to deal with.

I just bought the Zircon model and it's amazing. It even detects the BB in my knee!

I've got a few weeks or so before I have to make a call, so I sure appreciate the input. Any Cen-Tech scanner users here?

While talking of metal detectors how do you react when you find metal with the detector, and what are the methods used to extract it?
I am going to be purchasing a mill and have several friends in the tree removal business, so will have access to a lot of urban timber.
I hope this is not considered hi jacking a thread, if it is i apologize in advance.

I mostly cut "urban" logs and use two different detectors, a Lumber Wizard for 2-3 inches deep and an inexpensive "Bounty Hunter" which seems good for six to eight inches deep and often detects my log dogs or parts of the mill. I scan the whole log with the Bounty Hunter before I start and mark questionable areas with a lumber crayon.

If the Lumber Wizard beeps an alert I use a small chainsaw and a beater chisel to chop out the nail. The Lumber Wizard is usually accurate to within 3-4 inches diameter so I use the chainsaw to plunge cut a 3-4 inch square perimeter around the suspected area. Then I chop out the suspect area with the chisel or a large cat's paw. I occasionally hit a nail with the chainsaw so know that I need to sharpen frequently. Eye protection is important but I have that for milling anyway.

As I saw down through a log I'll stop every 2-3 inches on suspect logs to use the Lumber Wizard. Sometimes the Bounty Hunter will find something deep that the Lumber Wizard won't. In that case I'm now confident that I can saw a little deeper if the Lumber Wizard doesn't find anything, even though the bigger detector does beep.

X-ray vision helped, too.