I'm using a Cisco ASA 5505 50-user firewall in a co-location facility. The systems at this location are performing monitoring of additional remote sites (also running Pix or ASA devices) I've established site-to-site tunnels, but have hit the hard-limit of the device under its current licensing scheme. The ASA 5505 model is limited to 10 simultaneous IPsec tunnels.
I am curious about my options here. Ideally, I'd like to be able to handle 15-20 connections. From research, it appears that I can add an additional Security Plus license to expand to 25 VPN tunnels. The other option seems to be moving to a Cisco ASA 5510.
Given that I have a small number of systems at the colo, is moving to an ASA 5510 just to gain extra VPN functionality overkill? Are there any downsides (hardware/performance/etc) to upgrading the ASA 5505 to the 25-VPN option? Are there any other options I've missed?