It depends which network you are sending to and from. As a general rule of thumb, L1 to L2 transfers take the same amount of time than sending via the native bridge. For example, depositing from Ethereum to Polygon takes 8minutes via the Polygon bridge and the same amount of time with the Hop bridge. This is because Hop itself uses the native bridges for L1 -> L2 deposits.
The advantages with Hop come about when you transfer from L2 to L1 or from one L2 to another L2.
Here, the rule of thumb is that an exit will take as many blocks to be considered final (safe from reorgs) on the sending chain.
Deposits from L1
Ethereum -> xDai: ∼5 minutes
Ethereum -> Polygon: ∼8 minutes
Withdrawals from xDai
xDAI -> Ethereum: ∼2 minutes (12 blocks)
xDAI -> Polygon: ∼2 minutes (12 blocks)
Withdrawals from Polygon
Polygon-> Ethereum: ∼4.5 minutes ( 124 blocks)
Polygon-> xDai: ∼4.5 minutes ( 124 blocks)