I think this is one very challenging thing about this hobby. You want to make a "good purchase" - I.E. one where you spend right up to the point of where the diminishing returns become tiny in relation to your needs and budget. The problem is finding that true point for yourself isn't possible by just taking others' word for it. At the same time, unless you are very wealthy and you have an unlimited amount of time (or you review electronics for your job) it isn't realistic to purchase many different components to do comparisons. I would argue most of us don't have the energy to do it either. So you do research, read as many opinions as you can, decide which ones you trust and are meaningful to you and finally pull the trigger. Beyond that it depends a little on what sort of person you are. Some are happy with their purchase and move on with life; others are never 100% complacent and part of the fun for them is the hunt for improvement.Been reading up for endless hours about PA5 directly and related topics... with little to show for it. The considered use case for it? Well-measuring high-end speakers (Dynaudio Confidence C1, $6500 MSRP). Rated 4 ohm, with no measured dips below that. Most "conservative" audiophiles would consider it lunacy to even consider a $/€350 amp for that, just like I've gotten a lot of flak for my current amplification many, many times over the years. But given how much for more affordable high quality amplification is these days, I can't help but wonder...
My thinking is: there's more than enough wattage as I don't normally reach more than 1 Wpc peaks. Current handling seems at least reasonably good given the 72% increase in power from 8 ohm to 4 ohm (a good indicator is getting as close to 100% as possible, or so I've read). Obviously very clean measurements overall, at least for the usual ones amir does for his reviews. But can it really reasonably match up to such high-end speakers even so? With or without a subwoofer to lighten the load? Going just by measurements from what I understand I don't see why it wouldn't work for controlled, clean, neutral, detailed playback at the volumes I need. Excellent crosstalk seems to imply good stereo imaging as well, which is important to me. But these are hardly the only measurements one could make - yet even if more was available I'm certainly no electrical engineer, or particularly knowledgeable about the measurements and other super-technical considerations even from just a hobby perspective.
Subjective opinions I've found here and elsewhere are a crapshoot as usual when put together. There's such variance in opinions and so many biases in play, be it an "innate" dislike/distrust towards small devices and Class D from the "traditional/conservative" crowd, or disproportionate praise based on just the measurements without even owning it on the other end. Some users/reviewers praise it to high heavens with absolute terms, then end up saying it's nice for the price. Eh, not very helpful. Others think even cheaper products can match it, like from Aiyima and such. Some claim a lack of "power" even when not clipping - mainly referring to lower frequencies. Would not being closer to the ability to fully double the wattage at 4 vs 8 ohm really result in such, given no dips to below 4 ohm? I'm not sure what else it could be - so assuming the "lack" was real to begin with rather than the absence of some kind of coloring in the sound or something, what would even allow for comparison with other options without a live audition?
So it firstly becomes a question of whether it's a sane consideration to begin with, and then secondly how it compares to other options at various prices as well as my current Audio Analogue Puccini stereo amp ($700 MSRP), a 1997 model - whether it's a meaningful upgrade or not. While not super costly, I don't have exactly great finances these days so that I could afford "mispurchases". The core problem is not being able to audition/compare without buying. It's no wonder I jumped off the upgrade bandwagon after getting the C1s 11 years ago. Back then any upgrade path would've been even costlier than now.
One thing I do like is that now there are starting to be some high quality less expensive equipment such that if you want to spend a little time and money you can move slightly away from the "I'm happy, this is good enough" end of the spectrum towards the "I'm always looking for the next upgrade" side without feeling like you are breaking the bank. It's also now probably easier than ever before to sell used stuff such that the cost of trying things can be mitigated to small losses. I have been on the "I'm happy" side for a LONG time, but now I have the time and money to where I may start doing more experimentation. This PA5 is definitely something that would be fun to try out just to see how it sounds in comparison to my more expensive and powerful Emotiva XPA-2.