Lightroom 5, previewed here, is now available. The full price is $149, or $79 for an upgrade. It's available direct from Adobe. Alternatively, it is also included with your subscription to Creative Cloud.
IMO, this is a major upgrade and, given how essential Lightroom is for my workflow, I upgraded right away. I downloaded and installed the upgrade without any issues. However, please note that if you tried the LR5 beta, then LR5 will open your LR5 beta catalog by default. If you plan to use your old catalog, you need to open your old catalog, and you will be prompted to convert it (just to be sure, back it up before you do so). Be warned: converting your old catalog can take a while, depending on the size of your catalog.
I edited some of the party shots using LR5 and after I exported them, I noticed that some of the shots reverted to an earlier state in Lightroom. However, the exported shot is the correct version. This happened for a handful of shots. Not sure if this bug is unique to LR5. I was able to go to the correct version using History. Another weird effect: my S5 shots had a +30 saturation applied to some of them. I was editing the shots until 3am so I could have done that by mistake but it could be another bug.
One issue for users of Jeff Friedl's Picasa plug-in: it won't be imported to LR5.
Another bug reported by Jeff Friedl: you should not select images in a grid while in a publish service. See here.
ADOBE CAMERA RAW 8
If you use Photoshop CS6, you should upgrade to Adobe Camera Raw 8 to ensure compatibility with LR5. Just go to Help... Updates to check if you have the current version and update as needed. Do this after you convert your catalog because you may need to close Lightroom 5 to complete the Photoshop update.
ACR8 will be slightly disabled in CS6 -- you won't be able to add new effects such as radial gradient -- Adobe's way of coercing you to get a Creative Cloud subscription, notwithstanding the hundreds of dollars you already paid for CS6. Fortunately, if you have an image edited on LR5 or Creative Cloud with the new effects, the updated CS6 will be able to view the new effects (even as a Smart Object) although you won't be able to change the new effects.
For older versions of Photoshop, you can export from Lightroom as a TIFF.