Soler has been awesome at times. 1st in Burgos '07, 5th in Burgos '09, he was one of the three (alongside Antón and Mosquera) who did a number on Contador at Castilla y León - and he bridged across from the péloton to the three masterfully, which takes some doing. Soler's problem is that when he's healthy and on form he's one of the best climbers in the world, but his bike skills are atrocious and his body is made of glass, which means that he's seldom healthy and on form.
Cobo, one would assume, would have had to be pretty careful if he were doping on Fuji-Servetto last year given that they had to appeal to get access to the Vuelta and the organisers were after any excuse to exclude them. He managed to come 10th nonetheless, so I'd guess that's his talent level when on-form (he focused mostly on that race) and at a not-as-high-as-you'd-expect-at-Saunier-Duval level of program. Whether he was clean or not is a question for the Clinic, but I'd say that if he's dirty or has been dirty, he would have been less so in 2009 than 2008. This year he's had a bad year, but that happens. Igor Antón had an awesome 2008 and has been excellent so far this year, but he had a very pedestrian 2009, after an injury robbed him of most of the off-season and he couldn't get to proper race shape until far later.