In the example you give, it's not better. It's best practice to catch exceptions as close to the point they're thrown to avoid catching unrelated exceptions of the same type.

try:
    file = open(...)
except OpenErrors...:
    # handle open exceptions
else:
    try:
        # do stuff with file
    finally:
        file.close()

As unfortunately verbose as this is, the with statement doesn't allow you to catch exceptions thrown during its evaluation. There was a suggestion to add exception handling to this effect on the mailing list:

with open(...) as file:
    # do stuff with file
except OpenErrors...:
    # handle open exceptions

But this was shot down.

Finally it's worth noting that you can directly enter and exit context managers like so:

file = open(...).__enter__()
file.__exit__(typ, val, tb)

This is described in more detail here and here.

As a general guideline, with statements excel for cases where exceptions are not expected, and the default "enter/open/acquire" behaviour is adequate. Examples include required files, and simple locking.

In the example you give, it's not better. It's best practice to catch exceptions as close to the point they're thrown to avoid catching unrelated exceptions of the same type.

try:
    file = open(...)
except OpenErrors...:
    # handle open exceptions
else:
    try:
        # do stuff with file
    finally:
        file.close()

As unfortunately verbose as this is, the with statement doesn't allow you to catch exceptions thrown during its evaluation. There was a suggestion to add exception handling to this effect on the mailing list:

with open(...) as file:
    # do stuff with file
except OpenErrors...:
    # handle open exceptions

But this was shot down.

Finally it's worth noting that you can directly enter and exit context managers like so:

file = open(...).__enter__()
file.__exit__(typ, val, tb)

This is described in more detail here and here.

As a general guideline, with statements excel for cases where exceptions are not expected, and the default "enter/open/acquire" behaviour is adequate. Examples include required files, and simple locking.