opinion on Omega Super 3i speakers

Actually, the Omega Super 3i speakers have a 4.5" driver.

I have owned Omega speakers over the last 15 years ... the Super 3i, the Super 3T, and the Super 7 Monitor Mk2.  

Single driver speakers offer a different listening experience.  Very clear, coherent sound.  No crossover to add distortion or smearing.  Excellent with vocals and acoustic music.

Personally, I would save up the extra $300 for the Super 7.  I find that the larger driver has more power and plays louder than the 4.5 driver.  The 3i is no slouch either.  It plays fast and will keep up with most music that you will throw at it.  I just like the extra oomph that the Super 7 provides.

I have the Super 7 in a 15 X 12 X 8 room (L x W x H).  I use them with a Rega Brio R integrated amp, Unico CD player, and a Technics 1200GR turntable.  At one point, I had the Omegas paired with a Prima Luna PL5 (tube integrated) and it was a wonderful pairing.

The Omega web site has a very active user forum, which you may wish to visit.

Rich 

https://www.audiocircle.com/index.php?topic=134637.msg1429753#msg1429753

Here is a link to my impressions of the Super 7mk2.  

Rich 

Awesome, much appreciate.

I don't know about the Super 3, but just bought the Super 7 Monitors Mk2. I'm breaking in the speakers, so far they played for about 10 hours. 
I'm using them in a small room connected to a little tube amplifier (KingKo Audio KA101, 12W in push-pull using EL84 for power).
These speakers play loud without loosing on detail and clarity. Their sound is a bit to the warm side, I would say - not crisp and analytical. I like the combination with the tube amplifier. 
I guess these are an upgrade on the Super 3 and that's up to your room and wallet which model to choose.