So I ordered the 18 with the ciare super tweeter option. I had lately been going for a brighter sound and was struggling with various cabinets to make that happen. So when I saw the words "super" andf "tweeter" so close together I thought it was a good idea. I've only had 2 upright gigs with it but I gotta say it sounds great! It's a really good form factor, only feels like a few more pounds than the wizzy 10 I've been using but sounds like an extra 20-30lbs when plugged in! GREAT low end on this sucker. My drummer on Friday's gig: "I really like the subs coming out of it". Didn't need to crank it either gigs so I cant report on the volume. What I noticed was that with my Yamahiko single sensor pickup and Acoustic Image Clarus Series IV I had to turn the gain higher than I normally do. This is probably due to the lows the 18 puts out (since my understanding is that the lower frequencies use most of the wattage from an amp). Not a lot higher but higher. My guess is that in really loud situations my high pass filter will be much more useful than with my wizzy 10. You can't see it in the pics but there's an on/off switch for the tweeter located in the lower left port. I had a hard time hearing the difference between the tweeter on and off unless I REALLY cranked the treble knob on my Clarus. But in all fairness I just strung my upton ply with Flexocor Starks and those are REALLY dark strings. Kinda wished I still had my spiro weichs that I was so familiar with acoustically/with my previous cab(wizzy 10) for a better comparison. I also feel a little silly for getting the tweeter as I'm now trying to go back to a darker sound. Oh well! Options are always good and I bet the tweeter will be nice for electric bass work. I thought it was more to get the option with the side mounted speaker jack for using the cab as a monitor but was pleasantly surprised to see my cab came with one. Also, mike's wording initially led me to believe that when getting that option you only had the side jack. I'm glad to see it's in addition to the rear jack. So you can stand the cabinet up straight and use the rear mounted jack or use the cab upside down as a monitor wedge with the side mounted jack. Options are cool! Note the monitor option would probably get you some extra rubber feet, if I were to lay my cab in the monitor wedge position it would be resting directly on the wood and I don't like that idea at all! But then again, I don't think I'd use it like that and in all fairness didn't order the "monitor wedge" option just the "tweeter" option. Guess the side jack was a bonus! I mentioned that I just put on flex starks and that it kinda obscured my ability to judge the cab but I should say the first word that hits me with this cab is: clarity. Not in the treble sense but in an overall sense. There were acoustic subtleties with the flex starks that were actually coming out of the cab. The sound is so transparent, it's amazing. As I turned up the cab at home eventually I got to a point where I couldn't tell the difference between what was coming out of the cab vs. what was coming out of the bass. All this with a piezo! And the arco sounded so terrific! Granted arco had a tinge of piezo quality to it but it still sounded more natural than with the previous wizzy 10. And that's with the same pickup and head. All in all the cab really smooths out the edges of the yamahiko. It's new and there's always a honeymoon with most new things. I definitely need to put this cab through more paces but my first impressions are VERY positive. I've gotta say, while I don't have personal experience with the 16 (although a buddy has one), If I was considering purchasing a 16 I would definitely go for the 18 instead. Slightly bigger, slightly heavier, slightly more money but all in all you get what sounds like a typical 12" in a small 10" size.