The difference in performance was actually 2-5% in favor of Digium, so it was not a significant difference. Also, this was only on a system with a single quad T1 card.
As for the echo-cancellation cards, they do reduce the CPU load on the machine by 10-20% (it’s about the same for Digium and Sangoma models)
I have had quite an interesting(frustrating) experience with two Digium TE405P quad cards in a single machine. LONG STORY FOLLOWS:
I put two quad T1 digium cards in a server and had periodic issues like recordings randomly not working when bridged across cards and the occasional crash. Then after about 5 weeks, the PCI slot of the second card died, it just went dead and nothing else ran in it(both quad cards worked fine). So figuring that the motherboard was bad I put in a brand new motherboard and things went the same for about 5 weeks again and it happened again, this time I had switched the cards and it was again the card in the second slot whose PCI slot died. I then decided to just move the card to the fourth slot and that ran ok for a few weeks then that slot died.
Then I got another new motherboard of a different model and again the second slot died after a few weeks. I then moved the second card to the 4th slot again and called Digium support since I knew it was definately not a motherboard problem. They logged into it and said everything was fine and if it happend again I whould get another motherboard. After 3 weeks the 4th slot died.
Then I got yet another new motherboard(the 4th in this story for those of you not counting) of a another different model, swapped out the two TE405P cards from other production servers so everything was new in this machine and again the second slot died after a few weeks, then I replaced both cards in that system with Sangoma a104u cards(one in the 3rd and 4th slots) and they have been running fine on that same motherboard for the last 9 months.
As a side note, I put both of the Digium quad cards in other production servers by themselves and they are both running as well to this day.
I have no idea what caused this, but it was reproducable and calling Digium tech support lead to no solution so I went with Sangoma cards and my system runs fine now.
I know that Mark hates it whenever I mention that something about Digium hardware might not be perfect and that in doing so I am “hurting Asterisk”, but it does need to be said. I have heard from many other people who have had problems like this with multiple Digium cards in a single server, and I have also heard from several other people who have upto 3 quad Digium cards in a single server with no issues, so your experience may differ.
You need to keep in mind that Sangoma cards do have a 5 year warranty and Digium cards have a 2 year warranty. Also, I had a T400P go bad 2 years and 3 months after I bought it and Digium would not offer a replacement or even any trade-in value for it on a new card.