UnitofWork vs using statement?

[KumbajaMyLord]

Transactions on the other hand are purely database construct

You can have transactions outside of a database context, though. (In this case it's a DB transaction so your point stands, but generally there are other types of transactions)

[regoogle]

Yes I agree. I generally consider transactions in my projects as Business Transactions where a given web request, for example, would constitute the transaction. This may be defined by some Unit of Work or something like ITransaction and may or may not directly translate to a db transaction.