I would like to see map to have most of the textures done when I play it. Some dev textures are okey, but atleast something that makes it look like a real map.
It wont take long to change couple of textures.
But in other hand, it is much easier to do major changes to layout before the details.
this sort of mentality is why i often don't release the 1st public version with dev textures (sure there might be a few dev texture buildings here and there but for the most part i try to give building a basic sense of individuality and colour to appease people).
often i will block out a map and run around on my own on the map a few times to get some idea of scale and feel and take in what is my natural movement flow (cos looking at a map from above in hammer gives a very different perspective to when you're in 1st person, and what appears to be an obvious path from A to B might not be quite as obvious when you're actually down on the ground).
once i've done that, i will add in base level texturing and lighting. - this is partially for my own benefit though, by helping to set the scene. once that's happened in hammer, in my head i can start considering details and functionality of the areas. however, it originates from the overall mentality/comments i've been exposed to when releasing maps for the 1st time. your first debut can be your only chance to impress afterall.
i should perhaps mention however that when i started mapping, i didn't know about this community or what was offered here (i.e. the testing events).
overall the most important thing is to take advantage of what's available to you, and temper your 1st release based on that.
so definetly, keep it as simple and bare bones as possible (whilst retaining functionality, so don't skimp on adding a model or two for important cover points, or using a placeholder brush for the same effect), release it amongst a small group of friends who you can play it with, and/or on tf2maps. get it tested out, modified, updated, tested again, etc. But hold off on posting a new thread at 2F2F, FPSB, or the steam forums until you're at a point where people are feedbacking more about asthetics then they are about layout. once you've hit the point of your layout being pukker, you're almost home free. detailing can often be done in a single iteration (though sometimes it's hard to resist avoiding detailing completely until that time). - you still need to test it though, both on your own and publically, as you might miss some lighting error when you run through it yourself, or some of the detailing might open up new exploits (e.g. a series of pipes along a wall that allows players to get where they're not supposed to).
so hope that's helpful.
edit:
re-reading what i just posted, i wanted to add that as a hobby, mapping requires a great deal of patience (and i'm not even referring to the compile times there).
when you've just released your new version (or 1st release) you're itching to get on a server with 20-something other players and get it broken in. usually though you're gonna have to wait a couple of days before you can get anything approaching that at all.