Carlos' website is a very basic website design. It does have all the principal mechanics but it doesn't jump out at you and make you want to stay on the website to view more about him. It also only contains one piece of work, and it does have the breakdowns and everything, but it begs the question as to whether he can do more.
Randy's website is a little crowded in my opinion, it has everything on one webpage. The showreel is brilliant and has links to imdb and LinkedIn, with breakdowns below the showreel, but not shown within the showreel, which would show the breakdowns much more effectively. There's also advertising at the bottom of the page, which I believe is so unprofessional.
Pietro's website is small but precise, there are clear links to their showreel, shot breakdowns, filmography and resume. The only change is that I would have put the showreel on the first webpage so potential employers don't have to click around. The filmography link goes to imdb, which is a good idea as its such a good database for people within the Film Industry.
Mathieu's website is a simple design and very confusing. The front page has a sort of blog view which mixes everything together, and then menus at the top. There are a few things to point out, the website needs to be proofread as some of the English isn't that good, and also I'm not quite sure where he lives to offer him a job as he did a Masters in Kent but other courses in France. The title of the webpages are 3D modeller and VFX compositor, and then has links to 3D work and VFX work, this seems like he is unsure what he wants to do as a job, so he should only show the work that will get him a job.
With such an impressive resume and showreel, I would have expected more from his website, however, it's very unattractive and boring. He should consider spending time to redo the website from the ground up before finding another job (if he moves on from Pixomondo), so it catches the viewer's eye. The first and most important thing I would recommend would be to put his showreel on the home page so that it shows what he's good at and employers would overlook the poor website.