Question about the upcoming New Nexus 7?

I'm thinking of purchasing a Nexus 7 sometime in the next few weeks, but I realize that the new Nexus 7 that might be unveiled in Google I/O might be coming out around June this year (assuming they release it two weeks after I/O).

That said, how viable is the Nexus 7 as a purchase now? I've seen many complaints about lag, and I don't want to be stuck with a laggy device. And regarding the new Nexus 7; has any rumors been leaked yet regarding it? I only see the usual "bigger screen, better processor" rumor that every flagship device has. On a side note, how future proof is Tegra 3?

Thanks in advance!