It would definitely be more beneficial.
The issue with using HE's DNS servers is that it sometimes returns suboptimal IPv4 addresses when DNS global load balancing is being used by the site you're trying to visit.
For example, using HE's DNS servers, I occasionally get like 200-500Kbps/s to the iTunes Store. Changing the DNS to TSI's DNS servers and flushing my DNS cache immediately returns performance to 25Mbps. Changing back to HE's DNS and flushing the cache again slows me down to sub megabit speeds.
With IPv6, because TSI uses HE for v6 transit you always get a pretty optimal return address for IPv6 requests. If any DNS GSLB is used for V6 at all (and I'm not sure how common that is yet), the addresses you get back are provided for HE's backbone and your packets are headed straight there (probably via TORIX) anyways.
It's basically always -best- to use a DNS server directly attached to your local backbone to get optimal IP resolution. So I'd second/third/etc TSI opting their v6 DNS servers into Google's V6 whitelist.