If the D-88 was working I probably would have kept it, I just couldn't fix it myself and it would have been too costly to repair at least in my opinion of cost. It's just how Sony players are, the best in creative design and performance, the lower the reliability. Surface mounted capacitors of the time were very new and very unreliable, it's a large part of what fails in these types of portable electronics from this time period. Difficult to replace. The same can be applied to Sony cassette Walkmans, the most compact and advanced designs with extra features are the most failure prone, the earlier large budget oriented Sony players (like the WM-1) are often still working with the original belts and are easily serviceable if the belts need replacing. The Direct Drive models are worse than belt ones as the gears become brittle and break, it's not as simple as just replacing a belt with a new one.

For more recent portable CD players I would say Panasonic ones are somewhat unreliable. The most recent one I've found is having some slight issues which I'm trying to figure out, it's just not worth a lot in repair costs as it would only be worth around $20 fully working. Overall I've had good luck with Sony and JVC players, and some Panasonics. I don't really bother buying other brands too often.