An update from Jerez as I saw it today. Great access btw, with around 2/3 of the track available for viewing.
A mixed bag across the teams really. McLaren and Mercedes really stand out, along with Force India, Williams and Sauber slightly behind. Ferrari were a bit of an unknown for me.
Despite the running problems Sauber looked good. But they had real problems with getting the power down immediately after a gear change. Too much torque, and the rear wheels were spinning immediately. Ferrari also suffered this, albeit less so. Williams looked decent, but seemed to be pushing just that little bit harder than everyone else. Force India looked quite smooth and well within the car limits - they also sound like they have different mapping to everyone else as the engine note is deeper and richer.
McLaren were smooth and controlled, although on a couple of 8 lap runs they had to bring the car in early. The car was very stable though, and there was no spinning after a gear change, something which many suffered from. If you just judged performance on watching them on track, you'd be surprised to see them top of the time charts.
Mercedes were equally good. Romberg, especially after lunch, was a machine in just putting down lap after lap at the same pace. He was quicker than the Williams in what appeared to be a race simulation over double digit laps, and after a while had solved the wheel spin after gear change problem.
Kiki was a little more ragged, but didn't appear too rough. The Ferrari seems to have inconsistencies in putting down power after a gear change, especially when short-shifting when it either wheel spins or loses power for a fraction of a second.
Merc, McLaren and Ferrari all ran different maps under braking, either blowing the engine to spin up the turbo or use KERS instead. Using the former sounds a bit like the 'spammers in a washing machine' used by Lotus in 2011, but not quite as loud. The turbo is very noticeable trackside, but overall the sound is good - just too quiet. No ear plugs needed at all today - not even close.
Finally, every driver was short shifting in some unusual places. The low down torque must be really high, plus (and I can only guess at this) it still didn't sound like anyone was hitting near the 15,000 rpm limit. This is only day 2 after all, and they're not pushing anything yet.
On a personal note, I had a good chat with Marussia engineers over breakfast (mostly tracking online where the car was en route to the circuit) as well as a couple of engineers from Williams tonight and some of the Pirelli chaps at dinner. Nice relaxed atmosphere.
Looking forward to the next two days