I have used laptop in the past before switching to desktop 8 years ago, and I don't regret.
Cons?
1. It doesn't get slow after a year.
2. There's always an opportunity to upgrade instead of buying a whole new system.
3. Productivity is far more better in desktop compared to laptop
4. Doesn't get over heat and burns my hand!!
5. Big monitor, text are easy to read and no eye strain and hence can work longer in desktop. And when I get older, I can upgrade to bigger monitor for my ageing eyes!!
Disadvantage?
No portability is the only issue.