Maybe a bit late for your answer. Anyway maybe my answer could be of use to others here. I've owned Brio 3, Mira 3, and Elicit (new version). I have also owned the Sugden A21a. Brio sounds musical, and a bit homogenous with a slightly bright and entusiastic fowardness. Control and composure is fair. It sounds like what it is- an amplifier designed to be as musical as possible at its price, but with compromises- I believe Gandy himself describes it that way. There is a new Brio R I have not heard or used and so can not comment on that one.
The Mira 3. going from Brio to this we get a definite improvement in soundstage definition, and bass control. Though there is better bass control, reach is limited, once you get to a certain point, the bass does not continue to go down in frequency- neither does it get all soggy and bloated, it simply disappears, leaving you with good bass down to that point. Mira 3 Detail is better. Gone is the touch of what I'll call "dirty" treble of the Brio- the Miras Treble is improved, mainly in level of distortion, which you'll hear as a less gruff presentation through the mid treble. Eventhough the Mira treble is better, at the very top end there's still some tizzyness. A Tizzyness you might not ever notice unless you hear the Elicit.
The Elicit- the slight treble tizzyness is gone, treble is clean now. Bass is stronger with excellent reach, where the Brio and Mira 3 stop digging down into the bass range, The Elicit continues dredging. And it is a bass that is neither sterile nor soggy. The bass response is excellent for what I had expected of an 82 watt integrated. The bass is perfectly musical, The soundstage is better defined, but not dramatically so relative to Mira 3. The midrange is more assured in both musical sweetness and clarity, though the difference may not be dramatic to some, it has qualities that the Brio and Mira don't match. Things referred to as hardness and greyness are mostly gone. For another comparison, the Elicit has a small dose of the beautiful midrange of the Sugden A21, but make no mistake the Elicit can not quite match the Sugden A21a in the midrange. I prefer the Midrange of the Sugden A21a. But the Elicit has much better bass and an overall cleaner and less distorted treble than The Sugden A21a. The Elicit is more detailed too. Yet the detail is'nt segmented or spot lighted. The whole presentation of the Elicit is very good to excellent across the board. To sum up a response to your question. It will depend on the listener. Some might feel The Elicit is not leagues better than a Mira 3, and it isn't given the price differential. If you are seeking what I'll call "refinement" and a greater sense of quality that comes with the extra money, the Elicit is an easy choice IMO. The Mira 3 fell just a little short of what I want to listen to long term. I can live with the Elicit for sure (and have for the past 4 years), and I could very well listen to the Sugden long term, but it runs hot as a toaster oven (and that is no exageration). The Elicit is about as good as class AB British integrated amps get, which is very well mind you, but it is certainly not the last word. It definitely dishes out the musical goods and should be more than ample for most folks. However it does not have that boundless sense of reserve of some cost no object amps. But keep in mind the retail price of the Elicit is'nt peanuts. In general It likes to be played moderatly loud, that is the amps sweet spot, typically around half on volume knob. When you go much louder you realize it has limits. The overall character of the amp is one that has just a dash of musical sweetness with excellent bass, and good but not "hyper" levels of detail. Like the Sugden A21a I'd call the Rega Elicit a music lovers amp, but not to the extreme end of pleasing that is the Sugden. If you are coming for hi fi fireworks you may not like the Elicit. It goes about its business and goes about it well. Lastly it works great with RS3 which is what are connected to it in my system. A final note, I have never heard a Naim integrated like the Nait XS, but that seems like a comparable option. Other analysis I've read on the net put the Naim slightly ahead on jump factor, with the Rega being smoother through the midrange, with better staging (that impression does not surprise me considering Naim has typically not placed a great emphasis on the concept of "soundstaging"). The Nait XS seems worthy of audition. I guess it Depends on where your preferences and loyalties lie. I love British Hi-Fi (or what used to be British Hi-Fi) and especially love Rega. To the above poster Sugden A21a is better at low volumes than any of the Rega amps- that is a trait I've noticed with pure class A amplification, but you have to deal with the heat and a bigger energy bill.