Alvarion (ALVR) jumps on upgrade -- should you play along?

Alvarion (NASDAQ: ALVR) is a WiMax provider that offers wireless broadband systems throughout the world. This stock has been on my watchlist for quite a while with its very attractive balance sheet and positioning in a growth 'sweet-spot.' When the stock received an upgrade today it caught my attention.

The analyst covering the stock, Richard Church of C.E. Unterberg, Towbin, upgraded the stock because it's "the best-positioned pure-play on wireless broadband adoption and should see significant growth as WiMax gains traction." On the news of this upgrade Alvarion rose about 6%.

Is now the time to jump into Alvarion? Truthfully, the stock remains very speculative despite the coming growth in the WiMax space and the company has struggled to increase its revenues in recent times (revenues in 2006, 2007 and TTM are all roughly the same). Despite it's very nice balance sheet (nearly $2 per share in cash, no debt), I'd have to argue that it's worth sitting on the sidelines until convincing signs of growth appear to justify the stocks current valuation of more than 3x sales.