Provider to Blend with Level3

We have a network that is single homed with Level3 at this time in Dallas. They already have BGP and their own ASN and IP setup. Who would you recommend for a second provider in Dallas to blend with Level3? Assuming Level3 and this other provider would be the only two in the blend for a long time to come? Client was talking to TWT, but now that they are being bought by Level3 that doesn't make much sense.