Thought I would run some "non-scientific tests" to check :)
The Players:
TemplateToaster version 3.1.0.5305 - Full Version (TT)
Artisteer version 4.1.0.59861 - Standard Edition (ART)
WordPress 3.6 - fresh default install on HostGator; no plugins activated; only default 2013 theme and one each from TT and ART
The Method:
Each theme was created by starting the respective program, selecting the default "from scratch" method for a WordPress theme, and directly exporting as a ZIP; nothing else touched.
The Results:
ZIP file size:
2013 (downloaded from WP): 248 kb
TT: 138 kb
ART: 199 kb
- from Folder Properties after ZIP extraction
Size / Size on Disk:
2013: 397 kb / 540 kb
TT: 560 kb / 716 kb
ART: 530 kb / 724 kb
Files / Folders:
2013: 59 / 7
TT: 62 / 3
ART: 78 / 3
Validation - W3C Validators
2013:
HTML5 - 1 error - no pass
CSS3 - 30 errors / 58 warnings - no pass
TT:
HTML5 - 3 errors / 1 warning - no pass
CSS3 - 561 errors / 97 warnings - no pass
ART:
HTML5 - 1 Warning - passed
CSS3 - 5 errors / 92 warnings - no pass
Your "mileage" may vary :D