ACI Titan II vs. Rel Storm III

Titan II LE by a mile! Tighter and more accurate than a Storm III. As much output as the $2500 REL Stadium. The Titan II LE is the real standard in reasonably priced musical subs. If you take the time, the integration is absolutely seamless. REL used to be my fav until I heard the Titan II. Do give it time to run-in. Mine was still sounding better after at least 100 hard hours. BTW, as others have said, this is a beautiful piece of furniture. My ex-girlfriend even loved it:)
Positive Feedback, Soundstage and Bound for Sound all loved it in recent reviews.

In my opinion the Storm III offers much better integration. I tried them both side by side and although both are very good subs I was always aware of the Titan's presence. The Rel simply disappeared and I could feel it only when the music material called for it. For home theater use only you could be better off with the Titan.

Several friends and I spent the better part of a weekend comparing the Storm III vs. the Titan II. This was over a year ago before the LE came out. Both subs were well broken in. We played a large variety of music, we tried different placements, we adjusted levels and carefully tweeked the setups. Wasn't really very close. The Rel is good, but on many recordings it drew attention to itself, the Titan II never did that. The Titan II could also play to substantially higher levels without distortion. This isn't just something that is a factor for HT. A big difference on large scale classical music that uses a lot of percussion, pipe organ etc. With the Titan II we were also hearing more bass information and detail. The Titan II never lost the beat.
I've now had a pair of the Titan IIs playing in my system for over a year. In over 20 years as an audiophile I've heard countless systems in the loftier price ranges, I've rarely heard this quality of bass.
Considering the ACI is significantly less money, it is a pretty easy call. One of the nice things is that ACI has the 30 day money-back guarantee. I'd suggest that anyone who thinks the Rel is even close, (the Stadium III is probably a closer bet), get them both in-house, break them in good, tweek the setups, and I know which one you'll keep.