These computers are differents from one another. One is better than the others but each computer has nice featurings.
Shuttle is a powerful computer and the best of this computer is that it is the smallest computer. It is as small as "xbox", the famous videoconsole.
But Dell is a computer that has a lot of history and Dell computers are really good. The only problem is that it is not compatible with other computer stuff.
I think Acer computers are better than Shuttle and Dell computers. The company has a lot of stuff for computers and has a good reputation in this world. So I would buy an Acer computer because they are the best and also they're the chepeast.
For example, Dell computers have their own processors while Acer computers can use any processor like Intel or AMD, which are the best processors you can use. But if we compare Acer with Shuttle we can see:
Shuttle:
AMD AM2 and future AM2 multiple core processors
Acer:
AMD Athlon 64 x 2 Double Core 4200
The Shuttle processor is faster than Acer processor whereas Shuttle processors will be the fastest with "multiple core" and Acer has only Double Core.
Talking about price, Acer costs 649€ and Shuttle 599€. In this case, Shuttle is less expensive than Acer, but you have to buy other peripherics like a monitor, etc.
