Earlier this week, Adobe released Photoshop Elements 10. There is no trial version as of yet, so my information is only based on news articles published about it and Adobe's own PSE 10 website. Here are the primary new features of this version, along with some comments.
Painting any of 100 effects onto the photo. The classic way to apply an effect on just a part of the photo is through layers (specifically layer masking). This feature instead makes it easy to choose an effect then apply it to the image by painting the effect on the area you want to affect - in just one easy, intuitive step.
This feature has already been present as far back as Photoshop Elements 7 (Smart Brush). The difference is that PSE 10 paints the effect with more "intelligence" (similar to Lightroom 3's Auto Mask feature).
Let's say you want paint over a particular area (e.g. a hand) but the brush goes over parts that you don't want to be affected (e.g. the background). As far as I can tell from the demo, this feature will understand that you want to apply the effect on just the hand and will not apply the effect on the background even when part of the brush goes over the background.
I haven't tried this feature myself but if it works at least as well as LR3's Auto Mask, then it should be useful.
Comment: Picnik has many effects that are applied with a brush. Some of those effects require a subscription but many are available for free. As for the Auto Mask, I already have Lightroom 3 (a product I very strongly recommend despite its exorbitant price), and 95% of the time, the selective change I want to make is pretty simple like selective dodging and burning, and LR3 does that pretty well (yes, I use Auto Mask fairly often).
New effect: Depth of Field. Want to simulate a shallow depth of field? PSE 10 makes it easy. You can select the subject easily using the auto mask, then the rest of the image will be blurred.
Comment: If you have any experience with layer masking, this effect is pretty easy to do with previous versions of PSE. You might save time with PSE 10's faster/smarter selection brush but I don't know until I try it.
New effect: Orton Effect. The Orton effect makes your image appear to glow. PSE 10 now has this effect built-in.
Comment: I have Picnik Premium which has had this effect for a long time now. If you don't have Picnik premium, the Orton effect is not that difficult to simulate, and there are Photoshop actions out there that do exactly that, such as this one.
New effect: Picture Stack Collage. You know those photos that are made up of several other smaller photos that have been carefully arranged to form the larger photo? This feature simulates that.
Comment: Picnik has built-in collage templates but doesn't have this feature. It's a nifty effect but I don't think you can use it very often without it becoming cheesy.
Curved Text Path. You can now add text with a path that curves.
Comment: A simple but useful feature. Picnik doesn't have this.
Photoshop Elements 10 is $99.99 with free shipping until Nov. 20, 2011. If you have any previous version of Elements, you can upgrade for $79.99. If you're on the fence or waiting for the trial version, you might in the meantime want to check out Picnik as an alternative.