I must say I was pleasantly suprised with this package.
I am familiar with various NLE (non-linear edit) packages, am regularly involved with Final Cut Pro and Avid systems and have been a Pinnacle Studio and Pinnacle/Avid Liquid user for many years along with some use of Adobe Premiere. I have also dabbled with a few entry level video editor packages (that are really too simple to be described as NLEs).
This package most sensibly falls between the two.
While it is by no means a full featured NLE, it is certainly much more powerful than the likes of Windows Movie Maker or some of the U-Lead offerings.
Some have reported that the interface is cluttered, I beg to differ. For a package with such a rich feature set I found the interface to be both intuitive and uncluttered! Yes, there are a lot of buttons, but the layout is logical and the icons used are self explanitory in most cases. Where they are not, hovering over the icon explains what it does - you'll very quickly get used to what is where.
I realise that my experience with professional NLEs probably means that I am able to get to grips with this software a bit quicker than a novice, but there really is nothing to be afraid of here.
The problem with the simpler video edit packages is that you soon find that, if you have any creative ability, the software becomes restrictive very quickly. Where Pinncale Studio keeps things simple on the face of things, it is actually very very powerfull when you dig a bit deeper.
Power Director 7 Ultra offers up a bit more functionality through the main interface - the Picture in Picture and video processing functions for example - but does not lose simplicity because of this.
To be honest, I was very impressed with the functionality included, there are a host of video processing functions, stacks of transitions (though as with all of these types of software, most of the transitions are tacky and of very little use. In fact most of these should be avoided at all costs as they will just make your productions look amateurish and gaudy), PiP is useful and the interface is especially simple and intuitive (add a PiP element then drag and resize in the main preview window).
There are limitations, of course. In a package like this aimed at the casual home user there are bound to be things that it doesn't do that a full-blown NLE does.
The one ommission that really stood out to me was that the PiP track does not accept transitions. Therefore you cannot fade in a PiP element, or wipe it on, or fly it on or whatever you'd like to do. Its a small thing but it would make for smoother, more professional productions.
Some have complained about the music that the system generates. To be honest I did not try it on PD7U, but in my experience all of these automatic soundtrack generators are pretty aweful. Far better to dig out a CD from yoru music collections and use a track off that to cut to. (Here's a quick tip: rather than cutting your video then using an auto soundtrack generator to fit music to your edit, lay down the music track first then cut the pictures to match - much more effective! That's the way it's usually done professionally).
In summary then, this is a great package for entry level video editting that will take you a long way before it starts to stifle your creativity. The interface is simple and intuitive enough for you to really get on very quickly, and with a bit of creativity you will be putting together accomplished, professional looking videos (it's so intuitive I don't see why people are decrying the lack of printed manual, but I guess for some that's important).
An alternative to consider is Pinnacle's
Studio 12 Ultimate for a tenner more (still no printed manual though!). Studio will let you go further than PD7U, but it historically has some stability issues and the inteface hides some of the more powerful features that are obvious in PD7U. What's more, Pinnacle is now owned by Avid - the big boy of professional NLE.
One last thing to note is that you can change the video quality of the preview screen in PD7U. At first I thought the preview was pretty grotty, but if your processor can handle it, turn the quality up (hover over the icons below the preview screen to find the option) and the previews look much better - this works for SD and HD material. You'll still get glitches in transitions and processed video in the preview window though if your processor can't quite handle it - though these shouldn't make it to your final rendered production.