Photoline all the way.
I have used Photoshop in a professional manner since version 4, and up to CS6. About ten months ago I switched to Photoline - no 3d or video fluff, extremely lean (17mb windows installation file!), and the layer system sweeps the floor with Photoshop - really.
Its workflow is mostly non-destructive, and offers adjustment layers, layer effects, live filters that do not require smart objects, virtual instanced layers which update in realtime when the original is updated, as many layer masks as you want per layer, grouped layer masks, layer effects and adjustment layers can be applied to layer masks(!), multiple page support, full vector layers with pixel alignment(!), photoshop files with adjustment layers and layer effects compatible (which means they remain live in Photoline), Photoshop brush library compatible, each layer in the layer stack can have its own custom image mode set(!), and so on, and so forth.
Also full CMYK, RGB, Lab, Greyscale at any bitdepth (8,16,32bit) PER layer.
Aside from the 3d and video components, it is on par with Photoshop, and in a number of essential areas actually an improvement!
The newest beta version (only available to registered customers) was improved substantially again. (dark interface setting anyone?)
For example, I currently use Gimp and Krita as "plugins" to Photoline - imagine that! This way I am working on an image in Photoline, and when I need a specific Gimp plugin, I fire up Gimp from within Photoline, apply the effect, save and quit Gimp, and happily continue. It connects directly with (almost) any software that works with bitmaps. Most generic Photoshop plugins are compatible with Photoline as well (I use FilterForge and NoiseNinja, for example).
For my latest game I prepared, converted and built all the graphics in Photoline. It was a much more pleasant experience than Photoshop.
And I would have never thought I would ever say this, but: when I return to Photoshop CS6 it feels awkward. Photoline's workflow is mostly better. Not everything (every software has its strenghts and weaknesses), but overall it works more efficiently.
The website is pretty dire, but do not let that detract you from trying out Photoline: it's actually quite amazing. (Un)fortunately I've become a Photoline zealot. And for the price of two months of Photoshop CC, you actually OWN a perpetual license that runs on both mac and pc. It also runs off a portable drive or usb key.
The new version should be out in a month or two. So far the devs have listened to about 12 suggestions of mine, and added those requested features to Photoline!
Oops, forgot linky: pl32.com