I was in a very similar position to you about 3 yrs ago. My older Aragon 4004 MKII was going to cost about the same to repair due to leaking caps in the power supply. I thought the cost was too high and was thinking of buying a high powered used class A/B amp to replace it.
I ultimately decided it would be a good time to try out a high powered class D amp. I'd been reading several posts here on Audiogon that related good results from various class D amps.that offered free or low cost home trial periods and I became curious .
So I ordered a classDaudio SDS-440CS stereo unit for $630 on a 3 week in-home trial basis. This unit is rated at 220 watts into 8 ohms and 440 watts into 4 ohms. My Aragon was rated at 200 watts into 8 ohms and 400 watts into 4 ohms. I preferred a high powered amp on my 4 ohm Magnepan speakers and knew an amp that could double power output when going from 8 to 4 ohms was a good indication of high current capacity as well as quality.
This amp was 1/3rd the weight, size and price of the Aragon but outperformed it in every way; better bass, a lower noise floor,better dynamics, more neutral, more detail at all frequencies with a similarly smooth mid-range and treble that was never harsh, even before break-in right out of the box. I highly recommend not only this amp but class D in general. Class D also runs much cooler than other amps and are more energy efficient.
There are currently a lot of good class D amps on the market. I've since bought 2 more class D amps that have replaced the 2 other class A/B amps I used in my combo 2-ch music and 5.1 surround HT system.
I now use a pair of D-Sonic M3-600-M monoblocks (about $2,000/pr) to drive my Magnepan 2.7qr mains, an Emerald Physics EP-102 bridged stereo amp ($600 on sale) to drive my Magnepan CC3 center channel and the classDaudio now drives my rear surrounds.
IMO, some current class D amps are very good and outperform many good class A/B amps. All upside with no downside I've discovered in 3 yrs.
I've noticed a general irrational bias against class D by some here on the forums but there's really very little financial risk involved with many of them so you could try one and decide for yourself.
I'm not a dealer just a big fan.
Hope this helped you,