1. What happens if I need a binary available on the server? (wkhtmltopdf) 2. Can I choose the linux distribution? 3. Can cron jobs be set up? 4. What about stuff like scout/monit etc ? 5. What about redis/memcaches/mysql/postgres?
However, it is always good to remember, all the boxes are yours and you have shell root access to them. So if we don't support something right now, you can always jump on the box and do it yourself the the Pro way!