I don't own anything from Andrews and Mark but quite agree with Hollowdeweller regarding Koster.I like all the makers you mention and have blades from all.
Here's my observations based on the samples I have.
As far as fit and finish I think that that Brian would be #1 Koster #2 and Mark #3
As far as tempering I think Koster and Andrews are tied with Mark being behind them. The 2 knives I have from him vary slightly in their edge holding ability.
As far as eveness of the grinds Andrews #1 Koster #2 and Mark #3. The Andrews ones I have owned or used would shave from tip to ricasso out of the box. The Kosters were even but I had to sharpen them to get them to max sharpness. The ones from Mark one was perfect and the other I had to spend considerable time evening up the grind esp near the tip and ricasso. It was very sharp in the middle of the blade though.
As far as personal service Mark #1. He will make you exactly what you want a true custom knife. Also in my opinion if you have an idea he comes closer than any other maker I have worked with to actually making what I asked for. Brian is also good at this so I give him #2 but I'd give Mark the edge. He's also nearly as quick as getting back to you as Mark was. Dan is for sure #3 here. I don't consider his blades custom as much as semi custom. VERY hard to get a hold of due to the volume he's cranking out. Probably due to him being a 1 man operation. For instance Bark River is also semi custom but it is very easy to get a hold of Mike Stewart the owner. Also no chance of getting any sort of design tweaking from Dan. Also I got a Bushcrafter from Dan one time and loved it. So I ordered a second with Osage Scales. When it came he had changed the way he ground them to where the edge did not come all the way down to the guard like on the first I ordered. I asked if I could get a return. NO. Interestingly later due to consumer demand he changed them back. Comparing that to say Bark River if you don't like it for whatever reason they will fix it. I have no experience with returns from Andrews or Mark.
As far as what you get for the money I'd say Mark and Andrews are a tie. Andrews is more expensive but his knives are more higly finished. Koster I THINK is slightly less expensive than Andrews last I looked, but the blades don't come as highly finished or sharp and I don't like his handle contouring that well.
As far as the actual Bushcraft model I can't comment on Mark's because the 2 I have from him are true customs and really nice. I prefer the Koster Bushcraft to the Andrews one because the Koster is smaller and more compact although I think for people with bigger hands Andrews would be a better fit and he puts a lot more work into his handles.
Hope this all helps.
Many quirks in service, fit and finish... yet I'm not disatisfied. Just better know about it first so you don't get upset.






