I have experience with the following:
1) Kimber 84L
Small, slick, slim and trim and stainless. No integral recoil lug. Only 2 bolt locking lugs. No gas flange on bolt shroud. No integral rails. Very good trigger but too many moving parts and the trigger show was too curled/small. Small trigger guard. 3-position safety which I wish was 2-position only. Mine has a detachable box magazine which I'm not a fan of but in this day and age they are practical, and this is one of the better renditions I have seen. Flush in the stock, no rattle, positive click in, easy to pull out yet not accidentally. Parts are hard/impossible to get.
2) Defiance Ruckus
Must be one of very few SA Mauser style actions in the world. LOL. Stainless, nitride coated. Slick as hell. Integral recoil lug. But only 2 bolt locking lugs. No gas flange on bolt shroud. Double-square bridge with integral picattiny mounts. Excellent 2-stage trigger but complicated. 3-pos safety that I wish was 2-pos. LA would have been great, but I already have other LA, so SA was chosen for this one. But it does limit me in cartridge choices. However works with both box magazine or detachable box magazine. Can be put into a chassis. Rem 700 style action. I do not necessarily like Rem 700 but it is like a Jeep or Harley. You can find stocks, chassis and other part for it everywhere. This one being a "one of" almost, is limited in the safety/claw/etc. parts department but stock/chassis, accessory and trigger-wise just like all the other clones.
3) Winchester M70
Stainless Mauser style action that is very slick. Integral recoil lug, flat bottom action. The new triggers are nice but too many moving parts. No gas flange on bolt shroud. No integral rails or scope mounts. The claw extractor has extra parts (not sure why those were added). The guide grove on right bolt lug, makes it less prone to wiggle and makes the bolt smoother than most Mausers. Very cool feature. Bottom metal similar to Mauser 98/Brno so also very cool especially if you get one in stainless not aluminum, but alu is lighter. Parts should be easily obtainable.
4) Brno 21/22
Small-ring Mauser. Lighter than k98, yet all the other parts should fit. I like the round-receiver ones for stripper-clip notch, and I like the double-square bridge ones for the integral scope rails. I like the bolt shroud mounted safety on the left/thumb side, and I like that it is a 2-position one. I hate that it does not lock the bolt handle. No gas flange on bolt shroud. Triggers are same as on k98. The floor plate is easier to open than on k98 but still no hinge. Trigger guard is nice and big allowing winter glove use with ease. Spoon handles are cool, and these models have the best one of them all, IMHO. But sometimes I which they had a pear-shaped handle like on commercial Mausers. I have one transition model and it has the ZG47 bolt but not the bolt shroud. Very cool to handle but still does not lock the bolt handle and does not sit as flat as the spoon handles (they do have some advantage there). Many parts are interchangeable with mod 98 so still somewhat plentiful.
5) Brno ZG47
I like the double-square bridge with integral scope rails. Gas flange on bolt shroud. The trigger is better than most Mausers for feel but it is more complicated with more moving parts. The trigger shoe is also very small and curved (like Kimber above). Wish it was a bit more open/straighter. Trigger guard has enough front space but not very generous height-wise. Trigger uses angled sear and cocking piece surfaces requiring levers in the trigger to hold the extra force, hence more complicated triggers. The Safety is nice and 2 position only and it does lock the bolt handle. But the cocking pieces and firing pin are more complicated because of that, and firing pin weakened by the extra notches. Still better than most others. Parts form mod 98 can be made to fit or fit already.
6) Brno ZKK
I like the double-square bridge with integral scope rails. Some had built-in peep sights. No gas flange on bolt shroud. Triggers are complicated with many parts and combined with bold stop and ejector.
7) CZ 550
Same as Brno ZKK. No gas flange on bolt shroud. Trigger is better feeling but also very complicated. At least it is mounted to the receiver not like ZKK triggers partially on the receiver and partially on bottom metal.
8) Brno 98, VZ 24 or any mod/k 98 really
They are all nice and cool and best but I'm partial to my old country ones. I like stripper clip notch as integral part of the receiver. I like the simple 2-stage trigger. I like the tool-less take apart bolt feature. I like integral recoil lug and flat bottom receiver. I like the internal C headspacing ring. I like gas flange on bolt shroud. Parts availability is still relatively good. The simplicity of this action is breath-taking.
9) Oberndorf Mauser
Slickest factory Mausers ever. Intermediate one I do not care for due to firing pin parts availability, but it does have the front receiver ring longer so maybe stronger in that area and also allowing for longer barrel shank. I love the stripper clip notch and simple triggers. Though double set triggers are mode complex and in 2 sets of parts (receiver and bottom metal). Parts same as mod 98 (within reason).
So, which one would be best? Probably a combination of features - just like the different manufacturers tried.
I like the smaller dimensions of the Kimber and small ring Mausers/Brnos a LOT. And they will do me just fine. But for bigger calibers I would go with the regular sized action. Mine would have the Brno style integral dovetails for scope mount but with stripper clip notch. It would also have machining for Opticotechna claw mounts (unlike German claw these leave no moving parts in the receiver) for QD scope attachment. It would have thumb-side 2 position safety that locks the bolt handle on safe. It would have a gas flange on bolt shroud. It would have integral recoil lug, flat bottom and would head space on C-ring inside the receiver. It would feature the notch in the right recoil lug to ride on the inside rail ala Win M70. Maybe it would have the top rib on the bolt ala Mauser so it does not wiggle sideways either. It would have 3 bolt locking lugs. It would have the original Mauser 2-stage trigger but slicked up. It would have the commercial Mauser pear shaped bolt handle, but Brno 21/22 spoon handle bolt would be available. It would be available in ChroMo steel or stainless or titanium, all with Nitride or similar coating that makes them slicker and more corrosion resistant. It would feature tool-less bolt/firing pin disassembly.
I may have missed or misrepresented some features due to bad memory so feel free to correct me. Also, what I consider good or bad here is just food or bad "for me" so don't get your panties in a twist if you disagree.
