Williams have actually looked quite strong in testing, having both speed and reliability. They're so well off that at the first Bahrain test they actually practiced pitstops. Everyone else was just thankful to get a car out for 8 lap stints, Willy was doing practice stops. That's a very big deal. They may not have had the outright testing pace that Merc showed, but the quiet money is on Williams to open their account strong in 2014.
I don't know if they'll be able to sustain that competitiveness once the development war kicks off after the first few flyaway races and the series resumes in Europe. But I think Massa will be in early contention for podium finishes and wins in those first four events.
To be honest, I'm really stoked for them. I grew up a Ferrari fan, but I've always had a deep respect for Patrick Head and Frank Williams (who I think is the world's longest surviving quadriplegic), and Pat Symonds is also a personal favorite; I just love the way they go racing. My two favorite drivers may be Alonso and Raikkonen, and they may both be driving for my favorite team.... but I'll also be rooting for Williams Martini Racing this year.