Which integrated to pick...

If these are your only choices The musical fidelity A3 doubles down 85 wpc @8 ohms 170 wpc @4 ohms so it is high current. The Europas are 4 ohm speakers and a little low on the sensitivity at 88-89db and require current. I'd probably go for the musical fidelity based on this.

YBA's are known for the quality and refinement of their sound though. With the Europas it could sound fabulous. I don't know the 4 ohm power rating of this integrated however which is important for an inefficient 4 ohm speaker.

MF A3.

I have the A308 power amplifier in my HT system driving Vienna Acoustics Haydn loudspeakers.

The YBA YA201 is a very smooth amp. However, if you listen at lower levels, it might not be the amp for you. Unless it is at a moderate volume or better, its true sound doesn't come through. It kinda fades away at lower levels losing dynamics and contrast.
In comparison to the Audio Refinement, the YA 201 is more transparent, more refined and more powerful.
I have never owned the MF. I have heard it in demo's (for what that is worth) and thought it was a decent sounding amp. It doesn't have quite the warmth through the mids as the YBA but it is transparent and clean sounding. I would also add it doesn't have much grain.
With all this said, my choice of the 3 amps would be the YBA simply because it sounds higher priced than it is and can be had for great used prices. Other than the caveat of lower levels, it's a great little amp.

I have owned the MF A3, and the Audio Refinment Complete, never the YBA 201. Though I have never heard the Eurpoas, I have talked with people that have paired them with the AR Complete and have said fantastic things. The MF is a nice integrated, but based on the feedback I got, I would use the complete. (my favorite integrated by the way... I have owned six of them).

Because of my love for the complete, I really wanted to buy the YBA 201 many times. I was talked out of it by people that owned it. Serious quality issues, YBA switched hands just before those came out, and I hear the value just isn't there with the 201 like it is with the complete.

Only my opinion, and with limited experience so take my advice with a grain of salt..