Again it's difficult to give a yes/no answer because it depends on what your priorities are.
IMO, nothing in a new AV receiver/AV amp on the low side of £1500 will equal the Yamaha for true muscle despite what the spec sheets claim. If you still have the handbook, or you look up the specs on line, you'll see that they measure the power as a minimum of 110W in to 8 Ohms, full audio range, and at 0.015% THD. In other words, the amp isn't breaking a sweat, and still manages to churn out the sort of power specs that folk pay thousands for in Krell and ATI amps.
As £500 AV receivers go, the Sony 1080 is good, but it can't hold a candle to the power that the Yamaha delivers. You can see part of that in the way they measure the power out. They use 6 Ohms rather than 8. That means their 100W/ch in stereo @ 6 Ohms equates to 75W/ch in to 8 Ohms. They also use a higher THD figure. The numbers are very small (0.09 vs 0.015) so it's not easy to see the significance straight off, but there's a difference of a factor of 6. Allowing the amp to distort more is an easy way to get a significantly higher wattage. It's the reason why all those little Chinese T-amps are measured at 10% THD. The 30W or 40W some of them claim equates to 5~7W at 0.1% THD.
What's not covered in the spec sheets is stuff such as the size and rating of the transformer. I'll take nothing away from what the designers have achieved with modern AV amps and receivers. They pack a lot in a box for very little money. But when you lift the lid on some of these older receivers and amps and find that the transformer is capable of delivering twice the amp's claimed power, then you realise just how serious the designers were about the importance of effortless power delivery. Contrast that with modern receivers/amps. Here you'll find that the transformer is typically just enough to deliver the maximum rated power. There's no additional power reserve, and it's why the power output of these amps doesn't change that much when dropping from 8 Ohms (or 6) down to 4. At 4 Ohms, the power supply is being asked to flow twice the amount of current for each recharge cycle (50Hz = 50 times a second for UK mains frequency). It has to do this to keep up with the demand from the 4 Ohm speakers. But if the power supply was already at the red line with the 8 Ohm load then there's nothing left in the pot to satisfy this extra demand.
It's the same story with the capacitors. The transformer provides pulses of energy, but that's not useable directly by the output transistors or much of the other signal processing circuitry; it's too choppy if you like. What's required is something to smooth out those pulses: That's the job of the capacitors. They're energy reservoirs. They feed energy out in a smooth continuous flow. The bigger these reservoirs then the better the amp can cope with sudden demands for power when there's a musical peak or some explosion. The Yamaha has huge capacitors. They're way bigger than you'll find in current £1,000+ AV amps.
The AX1 and its siblings don't have everything its own way of course. Naturally there's a lack of the latest input connections and processing tech. DAC technology moved on too, so while the digital to analogue converter chips in the A1 and the AX1 would have been state-of-the-art for the AV market at the time, I dare say that there may be better tech out there in newer receivers. High-end power amps from Bryston, ATI, Mark Levinson, Tag McLaren/Audiolab, Krell etc use the donut-shaped toroidal transformers rather than the E-core laminated type which saturate earlier and don't generate the sort of flux density of toroidals. I'll give Yamaha its due though, their implementation doesn't suffer the transformer buzz that often goes with E-cores if they're not very well made and damped.
All that being said, if you can use a Blu-ray/UHD transport with an analogue multichannel output, or live with a maximum of DD/DTS bitstream signal, then you'd have to spend a serious amount of wedge on a new receiver to come close to the AX1's performance.
