IAIAN7  Historically, the Last.FM player has been inconsistent and unreliable, rarely doing correctly what it claims to do (especially iPod based scrobbling).

However, with the updates made to iTunes in summer 2009, Last.FM can actually crash the entire music system. Just to enable syncing with my iPhone, I had to completely wipe Last.FM from my system; the iTunes plugin, the application itself, and its preferences.

Not just a bad-but-usable application anymore, it's downright malicious. Please avoid if you wish to continue using iTunes+iPod/iPhone.  
(Version 1.5.4.24670)

IAIAN7  Very easy to use, but doesn't calculate window sizes correctly. It can look fine in the preview, even when using the automatic sizes based on the background image, but the final published window is larger than the background and shows a white border (approximately the same height as the title bar, which I would guess is where the miscalculation occurs).  
(Version 2.1.1)

IAIAN7  Great UI, and a nicer setup than most DMG apps I've tried, with the exception of icon placement! There's no snapping, no moving with the arrow keys, and when trying to move 1 or 2 pixels with the mouse, the icon will either jump back to its original location, or jump 2 pixels further away. This makes it impossible to align icons, or place a single icon in a specific location. Adding to the difficulty, the highlighted style used in DMG Canvas does not match the OS X Finder style, so aligning elements using the highlighted title region will actually NOT line up with background elements once the final DMG is opened in Finder.

If snapping and precise placement controls can be implemented (nudging with the arrow keys would be ideal too), this will probably be the easiest and nicest solution available.  
(Version 1.0.8)

IAIAN7  HSV, RGB, and HEX conversions were broken in version 1.7, and in the flurry of errors surrounding Dashboard's unpredictable 4096 byte limit, went unnoticed till version 1.9! Rest assured, it's fully functional again in 1.9.7.  
(Version 1.9.5)

IAIAN7  I believe it's not displaying twitters because of changes to the Twitter format. It used to work quite well (showing a list of previous twitters from all your friends), but now it'll only show NEW twitters. Once they're viewed, they disappear.  
(Version 1.2)

IAIAN7  While it's certainly set up and designed nicely, this application can cause rather severe problems. Running in OS X 10.4.9 (if the application doesn't crash first) the needle jumps around too much to determine a single note, in OS 10.3.9 it's actually 1.5 to 2 notes off! I tuned an instrument using this app, only to discover it was completely wrong when I double checked it against another program (well, and my ears!).

Until this program is updated (currently version 1.1), don't try it... it'll only cause grievous issues.  
(Version 1.1)