These instances are different though, they are able to burst CPU usage, just like Linode. AFAIK, none of the other EC2 instance sizes are able to do this.
Linode doesn't "burst" CPU usage. Processor time is shared fairly among Linodes on a host, and you can use any time that isn't used by others. It's worth noting that each Linode has access to four cores, so you can go up to 400% CPU utilization. For a good idea of how Linode's CPU performance routinely exceeds that of competitors, try this review: http://journal.uggedal.com/vps-performance-comparison
Semantics. The end result is the same: there is almost always a large amount of spare CPU cycles on each physical box, which can be utilized by instances to "burst" above their allocated capacity.
It's more than semantics. The term "burst" carries the implication that you only get something for a short time. That's really not a good reflection of reality in this situation.
Words have meanings and carry implications. By your logic, we might as well use the term "banana" instead. The point is that the concept doesn't reflect reality, and thus your point has no merit.
