A few tips to better leverage your F5 support:
1. The support portal does not have support for specifying multiple modules when categorizing a case. If you have an issue with multiple ones it's always better to select the more uncommon one (avoid LTM!). The majority of F5 engineers has been trained with LTM, but not all has experience with ie. ASM, AFM etc.
2. If you're unhappy with your currently assigned engineer, feel free to ask for a case transfer. This can be done via mail to firstname.lastname@example.org, or via phone. If you want to escalate or express your dissatisfaction you can always ask for the Duty Manager. If you want to provide positive (also important!) feedback many engineers has their boss in their mail signature. And of course, they have their (in my opinion) awful surveys.
3. F5 uses a "follow the sun principle" for their support, which means that they have support centers across the globe. Depending on your time zone, and when you call you might end up in a call center that is far off in terms of time difference. You can see this by the signature of the support engineer.
4. This might go without saying, but if you have an urgent issue, always call and state that you have an emergency. I've found that creating a case in the web portal and then calling is much faster than trying to get someone on the other end to hammer in my details.
5. More or less always provide a qkview. They will ask for it anyways and it saves one return trip.
6. If you have/suspect hardware issues, always try to run an EUD (End User Diagnostics). The support engineer will ask for it anyways.
7. If you have a serious bug you can request an engineering hotfix. From my experience F5 is often quite helpful with this part.
8. Even if F5 has offices around the globe you can't expect them to work on a case around the clock. If you want them to, ask for it from your support engineer. For your own sake: Verify this no matter the severity of the case.
9. Got core files in /var/core? Depending on the nature of the issue the engineer might want to have a look. Follow this article to generate an md5 sum file and upload them to the support portal.
These are my tips and tricks. Did you know them all? Do you have any to contribute?