best gold classic watches around 15k

Lange 1815 and IWC Portuguese come to mind. You could do JLC too, but I think you hit the sweet spot with them below $10k.

Not a big Vacheron or Audemars fan, but I realize those are the two obvious alternatives.

Breguet may be your sweet spot. There are some stunning options in the classique line. 

If you do go gold in that price range, best to hang onto it. Resell generally wont be all that good.

 

However if you by it second hand, you can get something you may have not been willing to pay for initially. But also if you sell later won't lose as much or anything at all.

Ive never really liked the patek 3919. IMO the non complicated pateks are pretty boring but hey if it floats your boat . If it makes any difference to you i get more compliments on my VC malte grand classique than my Patek even though it was literally half the price. I find VC does the "plain" watches a lot more elegantly than patek.

I find the less complications there are, the easier a watch is to read.and use. Service costs also tend to be less when you don't have a watch with complications.. I'd much rather own a Patek if I can find a good mechanical one in that price range than any other brand that's out there. Their level of detail and finishing is extremely nice benefit as well..

You would be hard-pressed to find any complicated Patek not requiring major service in that range. The addition of an annual calendar or chrono to the Calatrava/Nautilus typically increase the base cost by about 15-20K alone. 

 

The winners in this price range I think are still Breguet Classique, VC malte as mentioned above, and possibly an AL&S Richard Lange, which I've seen just above the target price used. Although I like AP, I'm not a fan of the Jules Audemars line which would be the comparison here. 

Yeah, that's not going to happen within the price range mentioned here.

It's bit off the beaten path that leads to the default Lange / Patek selection, but for me that was part of the appeal of this H. Moser & Cie Mayu:

 

 

Love the deeply concave bezel:

 

 

 

The beautifully finished movement incorporates a power reserve indicator:

 

 

 

Here's a beautiful version in white precious metal (I don't recall which) and center sweep second hand.

I don't think you are gonna find any complicated patek's in your price range even second hand. Brand New they are closer to 50k and second hand at best 25-30k. It seems like your heart is set on a patek though.

Here's a bling one I've had for about 15 years now. Worn maybe once LOL
Solid gold case and strap which is integrated to the case. Quite nice but too bling for me these days