The 870 handles a lot better without the extension. None of mine have a magazine extension for that very reason.
I have stuck with the 870P, the older 870SP, and the older Wingmaster guns instead of the Express or Tactical for the following reasons:
1) The older style magazine cap retention system common to those guns that is not present on the Express and no dimples in the magazine tubes.
2) No J-lock on any 870P and on the older Wingmaster guns. Of course, the J-lock is now parked in the dustbin of history.
3) I like being able to find old 870 guns at great prices and use them as the basis for guns customized to my needs and wants. Since I usually discard the stocks, buying guns with ruined wood usually means a less expensive gun. I especially like the older 2-3/4" Wingmaster as the samples can be found for very little, and I have no need for 3" shells other than in my dedicated rifled slug barrel which is on a Magnum 870SP.
That being said, an Express will do the job. I just am a bit picky about my tools.