According to Slashfood:
What’s the best instant coffee that beat out the OVER-MARKETED Starbucks VIA?

Here’s what the site had to say:

Our Winner
Café Bustelo Instant Espresso

Sip or skip? Sip and sip and sip again

Pass for brewed? Easily

Tasting Notes: We had to buy a second jar because our colleagues kept stopping by to “borrow” spoonfuls once word got out. It kicked the kiester of our office kitchen’s major label brew with a rich, bold flavor comparable to its non-instant incarnation. As much as we dug VIA, Bustelo’s more friendly per-serving price makes this the tip-top cup.