The Brompton is a much better folded bike (it's a lot smaller, it actually stays folded, it doesn't have exposed greasy parts when folded, you can use it as a shopping cart, etc).
High end Terns (Verge) are more like a normal bike with good components but they are nowhere near as compact when folded (likelihood of walking it into a shop and not getting yelled at is nil, unlike with the Brompton), they don't have as good commuter accessories as the Bromptons and they ride much stiffer (which is good or bad depending on what you are doing with the bike).
The Brompton is a much better folded bike (it's a lot smaller, it actually stays folded, it doesn't have exposed greasy parts when folded, you can use it as a shopping cart, etc).
High end Terns (Verge) are more like a normal bike with good components but they are nowhere near as compact when folded (likelihood of walking it into a shop and not getting yelled at is nil, unlike with the Brompton), they don't have as good commuter accessories as the Bromptons and they ride much stiffer (which is good or bad depending on what you are doing with the bike).
Source: own both