The audio research arc line- from top to bottom.

LS 26 without a doubt.
The second best pre-amp int the world

Would others agree that the ls-26 beats the ref3?

Sorry, but the REF3 is better than the LS26. I never before would have said that with conviction, but Audiogon member Theo has a LS26 and he borrowed, from a dealer, the REF3. I went over, (THANKS again Ted!) and took quite a few of my demo CDs to listen to. We spent about 3 hours listening. I was WOWED to say the least. The LS26 is a great preamp, but the REF3 is in a different league.

I heard more bloom and air around the instruments and a much wider and deeper soundstage. Better and lower bass response and more edge detail in the upper frequencies.

I haven't heard the REF5, but Theo has and said that it is even better than the REF3.

In addition to what MoFi mentioned about the short time I had with the REF3 I will add that my LS-26 did improve performance with the 6H30-DR tubes from BAT. These have brought the LS-26 to it's peak performance. However even at the peak performance the LS-26 is still not a REF3. And as mentioned as well the 5 exceeeds the 3 in every dimension. So based upon personnal experience to answer your question, a firm no, the 26 doesn't out perform the 3.
And with all the extra circuitry in the 3 compared to the 26 it is my understanding that most of it is dedicated to the power supply. It seems contradictory that more circuitry is required to make itself disappear from the signal path. Oh and your welcome Brad.

Agree with everything that has been said. I owned the LS-26 before upgrading to the Ref3. The LS-26 is a great amp and probably the best value in the ARC preamp line but the Ref3 betters it by a considerable margin. And now with many used Ref3s avail (because of the launch of the Ref5) I would go for a Ref3. The only other thing I would mention is the new SP17 which probably equals the LS-17 but also has a phono stage incl in case that interests you. Tone Audio recently reviewed it favorably.