Hi all, some nice thoughts on this subject and also some good insight. When I did the "List" I knew that not everyone would agree. That's the nice thing about this forum, a good exchange of ideas and thoughts. But this was and is my take on this.
To expound more on this, I'll give my take again on the makers in more deatail.
Arrizabalaga, a true best gun in every sense. They can and do rival some of the best Englsih makers, can't say anything bad about them at all, just one great gun.
Garbi, another top of the line maker, fit finish are superb. The only maker that does not use any power tools in their shop (they do have machine engraving on the Model 103, but it's not done in the shop). I do think they are overpriced as compared to other makers, Lots of hype, but other makers can and do match the quality at a lower cost. Still, a top notch gun in every respect.
Grulla, Excellent gun in everyway. Much the same as Garbi, very good marketing and hype, still a great gun, but again, cost is starting to climb. The workmanship is there, but sometimes a few shortcuts are taken on the finishing. The early UA guns were made by the same craftsman in the same shop and with the same materials. If you want a Grulla, get a UA it's the same gun, but cheaper.
Arrieta, Ah, my favorite maker. A good solid gun with quality work all around. Still basically hand made. This gun is a hunters gun. A friend of mine who knows his Spanish guns has stated that in Spain, Spanish hunters use Arrietas. They are made for lots of shooting (Driven of course) and stand up with very few failures. This is a good solid gun. The cost is reasonable, the "extra" options you want on a bespoke gun are free as compared to other makers (I learned this from John Boyd). My bespoke gun that I've always wanted will be from this maker. I'll be ordering it from John BTW.
AyA, Good gun with the name most Americans know. This gun is more of a mass produced gun than the others. Granted there is still hand fitting, but by and large, it's a gun produced in quantity. They are even now price point guns (Cabelas, LL Bean as examples). I've compared an AyA #2 with the Arrieta 557, to me the Arrieta is a much better finished gun. I've also heard that there have been some QC issues as of late with them. They are also the only maker on this list that still makes boxlocks.
It's hard to compare guns to one another when they are not in the same "class". The maxium of Judge the gun, not the maker comes into play. But we all do compare guns to one another, it's in our nature. We don't put a T. Barker hardware gun in the same class as a Parker. It's comparing apples to oranges. I have have a couple of Zabala's while not known as a great maker, they are by and large good guns. I would not put them in the same class as an AyA 4/53, the AyA is a better gun.
Not every maker is the same, and there are differences, in the end it's what you like, not me.
Anyway, there's my take again, you may not agree, but hey that's your opinion and I respect that.
All the best!
Greg