These are okay websites for mining over the cloud. These currently on top list because of two thing, they are very old and second they are paying. The only thing that we need to ask ourselves is are you willing to wait for longer period of times to get your roi. If time is not problem for you then you are good to go with these sites. However, most preferable sites on priority base is, hashnest, hash flare, genesis and then rest of the two sites. Genesis mining is pretty good with their support which is needed time to time and they on time payments really. You can find more about these in services discussion where people have created special topics. :-)