ERL or ER-8 on VPN

Hello all,

i will build a VPN network among 3 different sites. Site A, Site B and Cloud Server (either Azure or Softlayer). I will build 3 site to site IPSec VPN connections between those points. I will use only 1 LAN and only 1 WAN so no more ports than 2 are needed. I will not use any QOS and my users are max 20 per site. I think that the only question in my head is the fact that the ER-8 is faster than ERL. But is ERL enough for such a scenario? or ER-8 is necessary?

Thanks in advance