We are currently using SIP trunking with our Asterisk box through a small voip company over a high speed cable connection. Due to some service problems with our current provider we will be switching over to either SIP over a T1 data line, or a service called OneFlex provided by our local phone company which through an integrated appliance provides PRI's over a T1, but lets us use the bandwidth for data when the PRI's are not in use. As far as I can tell the quality should be the same as a standard PRI. So my question is this. With the T1 lines being basically the same and costs basically the same for 10 lines can I expect better call quality using SIP or PRI's with a high quality card w/ hardware echo cancellation? Thanks in advance for any input.