For my room, having two subwoofers turns out to be worse than just one, so it totally is up to your room. That was an expensive experience...
Multiple Subs - mixing models
Is it a bad idea to mix subwoofer models? I have two REL-328's in my dedicated listening room and recently I picked-up a nice used REL G-2. Curious to see how adding the G-2 impacts the sound and balance (main speakers are the Magnepan 20.7's). Proof is in the listening but curious if mixing sub models present special problems.