Just a couple Aperture/Mac comments here....
I dump my originals straight from camera to a folder called "NewPictures"
Immediately after I run a script to rename them yyyy-mm-dd-hour-minute-second[sequence]
I then import these to Aperture, and move the previously renamed files to a year-based folder structure (1997, 1998,...2014). I'll create a new 2015 folder when we enter 2015.
This works great for me...but the "problem" is that if I'm not in Aperture, it's impossible to find pictures that I've tagged with keywords, GPS, ratings, flags, etc. One of my longstanding gripes with Aperture is that all the metadata that you add to a picture is locked in the Library or some type of sidecar file. (The same is true of other apps).
IMO, attempting to use folders for any type of organization other than date or location is flawed, because a single image can only live in one folder. It's a hugely limiting constraint on being able to access images that may share numerous properties, or may have an ambiguous organizational property.
Recently I've been experimenting with burning the metadata back into the originals using the Export Originals command...which then writes (some of) the metadata to IPTC fields. One great advantage of this approach is that with the metadata written to the file, the metadata is now searchable using Spotlight, which solves the problem of not being able to find images outside of the DAM software.
However, it's an incomplete solution, because there is a lot of metadata that doesn't necessarily map into IPTC fields. For example, it doesn't appear that I can burn GPS coords (at least from Aperture).
This also presents a bit of a workflow challenge, since it requires importing the images, tagging them, then reimporting the images with the IPTC.
I've experimented with exiftool, which can definitely add the metadata, but the problem with this approach is that there is no UI for assigning metadata. I could create a bunch of scripts that could be run sequentially on images to add individual tags...but this would require a bunch of work up front to create all the scripts and would also be very tedious to apply them all.
From what I can gather, it *appears* that Apple may be trying to solve this issue (exposing metadata to the Finder and other applications) with the new Photos app. If this is true I think it solves a huge issue that all DAM software presents: essentially locking all the "value" you add to your photos within a black box. Of course each computing platform is it's own black box...but that's another story.
Ultimately, while a dedicated DAM certainly has it's advantages, the "lock in" and accessibility problems these tools imbue is frustrating and substantial. Like the OP, I am surveying the field of alternatives because Aperture will eventually cease to be a usable solution...and it doesn't have all the latest lens correction, noise reduction, etc features.
It's interesting (to me) that the quality of the RAW rendering engine and the image manipulation tools--while certainly very important--have taken a back seat to considerations of DAM portability and DAM lock-in. I've spent substantial time and effort making all my images searchable--and this provides incredible value when working with tens of thousands images. Finding a solution that enables me to preserve and access these data outside the context of a vendor-specific solution is hugely important, and I'm not about to trade one "black box" for another (Lr, C1, etc).