Thomas R. Stephenson:
No, is not. If it would be a matter of personal taste anyone could be a
designer whereas there are principles that makes design good or bad.
Maybe then you should in fact say exactly what you mean about good design. I've see a number of applications where the designers (and reviewers) said had a good design where the users said there was so much look pretty crud that they were impossible to use.
I see your point Thomas and I'll try to explain my statement as shortly as possible to don't bother anyone.
Firstly when I use words as good design and bad design I'm not talking about what I do like or dislike, that's something related to my taste, my preferences. I.e., saying that I like blue, or I like 3D graphics doesn't mean anything but what my preferences are. If I state that the stove in my kitchen suffer of a bad design, I'm not saying that I like it or not, I'm saying that the design of the controls to turn on the flame is not clear and even after years sometimes I still press the wrong button to turn on the wanted stove. Same thing with the doors: a lot of times we see 'pull' and 'push' on the doors as the design of the handles is not clear at all. A good design would make easy to understand whether we've to pull or push. A very good design would make this clear as well as the handle a nice piece of design. These two examples are not mine actually, I deliberately took them from a great book by Donald Norman The Design of Everyday Things.
I'm probably messing up the things here as I'm talking about stoves, doors and nice piece of design.
Well, stoves and doors are the 'content', in our case how the main core of Pegasus is designed. For example, since Pegasus is a powerful email client, if not the most powerful (I've really tried probably 99% of all free email clients around), of course it comes with a lot of options. How to find the options, remember where that particular option was last time I found it, it's kinda difficult. I guess for most of you it's different, but I'm speaking as an average user here. Remember the example of the stove, I've to be able to access the controls easily and not to discover every time where that particular control was and what it was meant to.
The nice piece of design is the 'container'. I can understand how this part become difficult to talk about. But even this area of the design has rules, and only after having understood those rules I can finally add "... and I like it!" because, if I'd just say that I like it or not, I would be unfair in respect to all the artists who spent their life refining and looking for better solutions. So, coming to our contest, a gradient in the toolbar is simply usefulness, and being the background of the buttons as long as the background for the main toolbar, the only that it actually does is add distraction to that area. Speaking of the icons, understand what the main icons mean is not easy, except perhaps for the font icon and the filter icon (ok and the phone icon, even if I don't know when I should compose a telephone message). In the same toolbar appears a drop down menu that reads "default". I have no idea what that means, neither why it's been place in that particular spot.
The second toolbar is more clear, at least the text helps. I can see another filter icon, exactly the same as the other one in the first toolbar, but they do different things.
Lastly there's a purely aesthetic matter related to the icons and why they don't look good. Today's interface are moving towards a completely different direction, accordingly to the usability principles. They are clean, essential, easy to understand yet appealing.
I think I've not been short, I'm sorry for that. It's a wide subject actually and I do care a lot about it and followed this matter for many years now.
Hope this may explain better what I meant.
Today luckily there are a lot of resources around, when I started in this field was much different.
Just to suggest a few I've quickly found googling about it:
http://www.usabilityprofessionals.org/upa_publications/upa_voice/volumes/4/issue_3/common_principles.htm
http://www.smashingmagazine.com/2008/01/31/10-principles-of-effective-web-design/
http://www.usabilitybok.org/design/p287
Two actual examples of quite good design in other email clients:
http://www.postbox-inc.com/index.php
http://lifehacker.com/#!5479009/inbox2-desktop-combines-and-task+ifies-your-email-and-social-networks
@ anbecker: what do you mean about social behavior and people who complain about free software? please, could you elaborate this a bit more?