The tests that have been carried out on February 5th, 6th, 7th and 8th in Jerez, have given much of themselves. Sauber has been the team with more laps done, and the least has been Ferrari, while Force India was the team that tested more drivers. All this and more discussed below:

Felipe Massa made the fastest time of all four days, but the Brazilian said that time does not have much value as Jenson Button, with the hard tires on the first day made a time very similar to his own, and also the track had less grip track. Therefore it means that McLaren is ahead of Ferrari, at least in terms of classification, but apparently also in race.
Both Lotus dominated the timesheets 2 of the 4 days of testing at Jerez. On Wednesday Romain Grosjean did it and Kimi Raikkonen on Friday. Lotus seems that in qualifying will be within the top 5, but in the race, it seems that this performance will be lower, so they would be in a similar situation as Ferrari.
The fifth best time was Sebastian Vettel’s, with the hard tires This suggests that the Red Bull Racing team could be very good when it comes to the race, and that the car is made by Vettel’s philosophy rather than the philosophy of Mark Webber, since the Australian was only the fifteenth fastest time of the four days with the media tire.
The Mercedes team has worked against the clock during these tests, since the first day Rosberg could not do many laps due to a fire in his car, and the second day Lewis Hamilton had problems with the brakes, so the Englishman did not do many laps, as well as his teammate. The next two days, each driver of the German team did almost 150 laps per day, a hard work, to recover the wasted time, which suggests that this team can be good in the race, but not too much in qualifying.
This would be referred to the best teams in Formula 1. On the other hand, teams of the middle of the grid do not show at all what might happen in the year, with these tests.
We have seen how the Toro Rosso goes well in classification, which suggests that they may enter more than once in Q3, and in race also seem to to go well. This allows us to think that this team would be the first in the middle of the standings.
In Sauber things also seems to go well in qualifying, which make that the entrance to the Q3 will be more disputed than ever. But in race, Sauber seems to be behind Toro Rosso.
Waiting for the release of the new car, Williams seems to be the next team in the timesheets. The team from Grove, who has trained in theory with the car used in 2012, in practice this has brought many changes, so it seems that Williams will not highlight even in qualifying, or in race. But we should be looking forward to the staging of the new car that will be presented on February 19 at the Circuit of Catalunya.
Jules Bianchi only drove on Friday, as Force India wanted the Frenchman to see the difference with the cars from 2012 and 2013. It seems that, with the third fastest time of the four days of testing, and getting the second place in the last day in which he only did 56 laps, Bianchi could be closer to achieve the only official seat that has not yet been confirmed. The Indian team looks like it may have a good race pace, similar to Sauber, but in qualifying is absolutely dangerous, as it may give surprises this year as well.
As for the two new teams from 2010 that remain on the grid, Caterham and Marussia, these seem to be closely matched in both race pace and qualifying, but both teams are far from the rest, the objective will be thus, avoid ending last.
Here you have the combined results of these four days of testing at Jerez:

Pos Driver Team Time Laps Tyres
1 Felipe Massa Ferrari 1:17.879 227 Soft
2 Kimi Raikkonen Lotus 1:18.148 123 Soft
3 Jules Bianchi Force India 1:18.175 56 Soft
4 Romain Grosjean Lotus 1:18.218 149 Soft
5 Sebastian Vettel Red Bull 1:18.565 198 Hard
6 Esteban Gutierrez Sauber 1:18.669 252 Soft
7 Jean Eric Vergne Toro Rosso 1:18.760 117 Soft
8 Nico Rosberg Mercedes 1:18.766 162 Medium
9 Jenson Button Mclaren 1:18.861 120 Hard
10 Lewis Hamilton Mercedes 1:18.905 160 Medium
11 Sergio Pérez Mclaren 1:18.944 179 Medium
12 Paul Di Resta Force India 1:19.003 240 Soft
13 Daniel Ricciardo Toro Rosso 1:19.134 153 Medium
14 James Rossister Force India 1:19.303 61 Soft
15 Mark Webber Red Bull 1:19.338 174 Medium
16 Nico Hülkenberg Sauber 1:19.502 178 Medium
17 Valtteri Bottas Williams 1:19.851 178 Soft
18 Pedro de la Rosa Ferrari 1:20.316 51 Medium
19 Pastor Maldonado Williams 1:20.693 155 Medium
20 Charles Pic Caterham 1:21.105 166 Soft
21 Luiz Razia Marussia 1:21.226 133 Medium
22 Max Chilton Marussia 1:21.269 107 Soft
23 Giedo Van der Garde Caterham 1:21.311 152 Medium