from box that does v4 with 25 MB/s and stalls with v6:
fs@bastion:~$ traceroute6.db 2001:558:1002:4:68:87:29:36
traceroute to 2001:558:1002:4:68:87:29:36 (2001:558:1002:4:68:87:29:36), 30 hops max, 40 byte packets
1 ge-1-2-0.cr-sirius.cgn1.hosteurope.de (2a01:488:fade::ba:c1:2) 0.416 ms 0.504 ms 0.593 ms
2 dssd-s2-rou-1022.DE.eurorings.net (2001:680:0:800f::1a1) 1.260 ms ffm-s1-rou-1022.DE.eurorings.net (2001:680:0:800f::1a5) 2.931 ms 3.043 ms
3 * * *
4 * * *
5 * nyk-s1-rou-1001.eurorings.net (2001:680::134:222:86:229) 95.185 ms *
6 2001:559:0:1f::2 (2001:559:0:1f::2) 91.304 ms te-0-10-0-4-pe01.111eighthave.ny.ibone.comcast.net (2001:559:0:1f::1) 88.750 ms 88.362 ms
7 te-0-10-0-4-pe01.111eighthave.ny.ibone.comcast.net (2001:559:0:1f::1) 89.617 ms pos-1-7-0-0-cr01.newyork.ny.ibone.comcast.net (::ffff:68.86.87.169) 93.361 ms 2001:559:0:1f::2 (2001:559:0:1f::2) 90.099 ms
8 * * *
9 te-9-4-ar01.ndceast.pa.bo.comcast.net (2001:558:e0:3::2) 93.070 ms te-4-3-ar01.philadelphia.pa.bo.comcast.net (2001:558:0:f668::2) 94.607 ms te-9-4-ar01.ndceast.pa.bo.comcast.net (2001:558:e0:3::2) 94.984 ms
10 te-9-4-ar01.ndceast.pa.bo.comcast.net (2001:558:e0:3::2) 94.421 ms * te-4-3-ar01.philadelphia.pa.bo.comcast.net (2001:558:0:f668::2) 93.290 ms
11 speedlab-www-ext01.ndceast.pa.bo.comcast.net (2001:558:1002:4:68:87:29:36) 94.848 ms 94.871 ms 92.901 ms
fs@bastion:~$ traceroute6.db 68.87.29.36
traceroute to 68.87.29.36 (68.87.29.36), 30 hops max, 40 byte packets
1 ge-1-2-0.cr-sirius.cgn1.hosteurope.de (80.237.129.97) 0.251 ms 0.290 ms 0.329 ms
2 xe-0-1-0.cr-pollux.cgn3.he-core.de (80.237.129.114) 0.191 ms 0.190 ms 0.185 ms
3 62.157.250.113 (62.157.250.113) 0.813 ms 0.844 ms 0.866 ms
4 217.239.37.62 (217.239.37.62) 86.849 ms 86.848 ms 86.841 ms
5 te-1-10-0-0-pe01.111eighthave.ny.ibone.comcast.net (75.149.228.117) 87.336 ms 87.331 ms 87.325 ms
6 pos-1-12-0-0-cr01.newyork.ny.ibone.comcast.net (68.86.86.193) 90.502 ms 90.352 ms 90.339 ms
7 te-4-3-ar01.philadelphia.pa.bo.comcast.net (68.86.91.162) 92.005 ms 92.077 ms 92.172 ms
8 te-9-4-ar01.ndceast.pa.bo.comcast.net (68.86.228.2) 96.593 ms 96.681 ms 96.779 ms
9 te-4-1-ur03.ndceast.pa.bo.comcast.net (68.86.134.29) 96.418 ms 96.523 ms 96.559 ms
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * *^C