Router recommendations for small DC looking to connect to large IX

Hey,

I am looking for some pointers to figure out what type of router I will need for the following situation:

• Small data center with a few hundred (soon few thousand) virtual machines (all publicly reachable)
• A single transit provider (might change in the future)
• Plans to connect to several IXs (AMSIX, DECIX, some small local ones)
• Current traffic: ~3 Gbit/s, we expect that to grow steadily but are not sure how fast we will reach 10G
• Sflow/Netflow or similar functionality
• Some filtering ability (nothing fancy, as of now just dropping certain ports during attacks)

Historically we were using an Arista device that needs to be replaced (EOL). The quotes we received for the successor device is way out of our budget (and we were hoping to get 2 for redundancy/fallback reasons).

My current thinking is that we must take care that the RIB of the device can hold enough routes we that we might receive via the IXs. Is there anything else I should look out for?

Thanks for your input :)