Hello dear "Dark Overloard"
First: Sorry man.. I did not see that interesting thread, just discovered it now ;)
Starting with, I want to say:
I love the K2 (Kalmar-2)!!
I love the Orca!!
I love the K1 (Kalmar-1)!!
In all in various orders :) LoL
Saying that, see below some personal points from my side:
1) For diving purpose all of them are EXCELLENT, but I have a preference for the K2 OT 8K: the best at all levels and number one dive watch in the World all categories: reading is fabulous thanks to its 8.25mm sapphire, it is like zoom, big bezel easy to manipulate / rotate, Titanium Grade 5, ideal size, screws at the lugs, etc... all is perfect on this watch for all types of divings.
2) I am having a small wrist: K2 and Orca, and even K1 are great in that order.
3) K1 / K2 / Orca on the H2O bracelet => same absolutely perfect wearing feeling, a must have! On any kind of rubber bands: all is excellent too. With any other leather/exotic straps: K2 is great; K1 is good too. For Orca it is a bit depending of the case you have: Dive case: super; Dress & Vintage cases: very good; Torpedo case: great too; Mono and Mono 2 cases: OK, but sometimes the watch turns around my wrist or too tight on my wrist: better on rubber or perfect on bracelet or mesh too ;)
4) K2 / Orca Dive / K1: the 3 of them are sharing the same case design with the same inclined lugs that I very very like!!! First it brings an excellent stability and positioning of the watch on the wrist, secondly it brings an additional comfort, and personally gives me more confidence because it fits well to the wrist (surrounding it) so less risk of pulling at the lug sides during scuba diving. Another small detail: the visual integration of the inclined lugs with the strap is top class, I very like it.
5) K2: I like to swap bezels; K1: I like to swap bezels and crown guards; Orca: I like to swap inner case. This customization part and the possibility to buy extra parts: like bezel outer cases for he Orca: it is the beauty of the H2O watches that nobody else has got in a such strong and solid quality :) And affordable price too!!
6) In term of design and day to day wearing: K2 is the most modern and sophisticated one, the case is the lowest compare with the K1 & Orca. The K2 is very fashionable with its inclined bezel and domed sapphire which are perfectly integrated with smooth curve / parabolic shape: so perfect for the work / diving / dinner. To me the K2 is the best from all H2O expertise / knowledge from the K1 & Orca. K1 is the first H2O watch if I am not mistaken, so it has this solid Dive watch TOOL feeling that I am very like. It is the biggest in size / diameter on the paper; but wearing it on my small wrist I do not see big difference with K2 or Orca. Like the K2 and Orca: The K1 is very addictive and the K1 is having the BEST quality / price you can find on market for a perfect quality and super robust dive watch. I personally very like the case back with its sapphire window and the cheery on the top of the case: it has nice Hex screws which allow you to open it easily the case back with the same screw drivers delivered with the watch. Visual experience the K1 is to me the watch which shows the most of metal, with all the nice metal brush iridescence, especially on the left side of the case which is not equipped of HEV (like the Orca too; only the K2 is having a HEV system). The Orca is timeless, this is a big point for this watch. The Dress case, Vintage, Dive, Torpedo, Vintage are gorgeous and very versatile and allow so many nice "combo" options and can be wear for classic / sport / etc... You have 4 sapphire size options: flat, and domed: 2mm, 4mm and 6.7m: all of them super good and different look of the watch. The Orca is top addictive, bronze option is amazing too. Just one comment on the Torpedo case which is one of the most comfortable H2O watch with its "Turtle" shape; but be informed that it has spring bards and not screws (that I much prefer generally); but again amazing to wear, you totally forget you have it on your wrist in 5mm.
So in Summary:
If you want / wish to get only one H2O watch for your collection => Go for the K2. But to me: you cannot get only one single H2O :) So get one Orca too, it is a must have. And if you are looking for a good tool that you can trust, then add one K1.
Anyway, you cannot do any mistakes, and you will never be disappointed by buy a K1 or K2 or Orca. They are Top Star professional dive watches, and super class and stylish :)
PS: I am having several K1 / K2 / Orca (maybe too much) => all of them are pure LOVE, there is not one that I do not like ;) Oh my God... I am afraid to be polygamous... Please do not tell my wife number 3 (LoL)