What are the best card?

My enterprise going on VoIP, so we have to remove all traditional telephony device for the suitable card for the connection with telco, this enterprise have about 80 E1/T1 lines for telephony. The migration I think is that would be a gradual process, so first I want to know which is the best card in practice: Digium or Sangoma.
I want to know:
1.- what is the most hardware/driver compatible.
2.- what is the most stable.
3.- what is the most scalable.
4.- what have the best performance with or without the echo-cancellation.
5.- experience about other design like this.
I really appreciate any help…
Best Regard.

If you environment is that large I would not put digital cards in the servers. You would be much better off using a media gateway.
Audiocodes Mediant 2000 supports up to 16 T1\E1 lines per device. If you went with the gateway devices you could have multiple servers for load balancing and HA.

Thanks for your reply.
Let me explain the situation more exactly. The enterprise have about 80 E1/T1 but not in the same place. The enterprise are divided in many remote office (large, medium and small office) and the most of those office has merely an E1/T1. But in some cases the number of E1/T1 lines are between 5 or 7. I using right now in some test a trunk with Cisco and work fine, but I think that the final result should be as simple as possible at least for large and medium office. I have already tested with Audio Codec and work fine too.
For this reason I want to know which of those card has the best performance, i read time ago that the digium’s card have some issues, maybe now this problems were solved.
Best regard.