I own a number of these bowls in a variety of sizes and they are fantastic.
2L bowl - Is great for general cake batters, whipping cream - jobs where you don't quite need the size of the Faringdon Stainless Steel Mixing Bowl, 3.5 Litres
that's also available
1L bowl - This is probably our least used size but I still like having it available, I often use this bowl to melt chocolate over a small pan of water as the bowl fits better than the larger 2L bowl.
500ml - I generally use this for mixing salad dressings in with my magic whisk or just for preparing my mise en place.
Pros (for all sizes):
Durable - after 12 months of serious hammer they don't look at all tired.
Easy to wash - mine have been through our dishwasher as well as regularly hand washed, no problems so far.
Can't think of any at all, the only thing you need to keep in mind is that you cannot use these in a microwave.