Originally posted by Architecture Fantastic post, thank you.
It's very difficult to decide, though I'm currently leaning toward the DA 15. It might be more expensive, less sharp and slower, but it differentiates itself from the 35 Macro more than the 21 does. The 21 does look like a fantastic semi-wide walkabout, however.
Decisions, decisions...
Only limiteds I currently have are the 35mm macro and HD70.. so my opinion holds little weight.
I've been bitten by the limited bug. I really like what I've seen from the DA 15. To me it symbolises the limited lens series; a 15mm in a small package (who else offers that?) and produces some great images and has some quirky aspects to its performance (slow aperture, curved focal plane etc). As you've pointed out it has its own fan thread where people really enjoy using the lens. Brand new it sells for roughly the same price as the Da21 (here in the UK), but the resale value of a used Da15 is much higher. The UWA view at 15mm looks like a lot of fun, and used correctly can produce some breath taking pictures....
So, the Da15 will be my next limited? No! The Da21 is right at the top of the want list. It's not as dramatic in terms of field of view, it's not as original (many other brands have faster pancake lenses around that focal length). I spent the majority of the first half of last year using my X100, which as a similar fov (23mm on an APS-C sensor); and I found it a brilliant walk around focal length. I don't know if it's a Northern English thing, but everything tends to be a bit smaller side (buildings, rooms, spaces) up here and whilst shooting at a normal focal length (35mm limited) it's often too tight. I found with my X100 that it was really useful for environmental portraits... which at the end of the day is what I'd find myself shooting.. I want people I know in there and I want their environment for perspective. The low 20s might not be considered the most flattering focal length for these kind of photos, but neither do they seem to suffer from the really extreme UWA type of distortion you'd get with the Da15. I could see me myself being very happy with lightweight walk around setup of the Da21 on my k3 and the HD70 - similar to what KH1234567890 seems to like (looking at the pics on this thread) - I really wonder if it IS a living in northern England thing!
Basically, my own choice in your situation would be the Da21mm; but I know I'd spend more time documenting sightseeing with my family, rather than being let loose to solely pursue photography (although in a perfect world I'd also have the Da15 in my pocket along with the HD70!!!)