The best 8port ISDN BRI board

I need to buy 8 BRI port ISDN BRI board but I don’t know which board is better. I have few choices:

  • OpenVox B800P (with or without SoftEcho??)
  • beroNet BN8S0 Asterisk PCI Card; 8 BRI ports
  • Sangoma A500 8 port
  • Gerdes PrimuX 8S0 PCI Card

Can you suggest me which is the best or at least the one which you have used and have good expirences.

Does PCI-X or PCI-E card interface has any influence in functioning?

thank you very much