We have a MX480 and utilized around 100 localized bgp flowspecs and 800 flowspec rules making a total of 900 flow spec rules.
The routing is setup on a "stick" an example is as follows
MX480 <=ae0=> QFX Switch <=> peeers
^
|
ae10
|
<dstribution routers>
We had some attacks that hits at 2-4 million PPS which basically renders the whole network useless. The inbound packets comes in but never delivered to its respective locations.