Lol. The Shimano vs. Daiwa threads always have the most posts! Well, I guess it's time to plug in my input. Before I begin fyi I have both Shimano and Daiwa reels (along with one Abu Garcia) current generation and older.
In terms of spinning reels, I feel there is actually quite a bit of differentiation now among Daiwa and Shimano lines that's it's really hard to compare now. I feel that Daiwa is trying to make things a little lighter in the Ballistic and other reels vs. Shimano which I feel has some robust reels. And each reel has their own feel to it making any comparison an apples to oranges one.
In terms of spinning reels even the mid tier Daiwa reels now have mag seal technology which is supposed to keep water out of the reels which means you don't have to carefully stuff your reels with grease like I do if I dunk my reels which happens about once every two trips for me. It doesn't really matter to me as I usually do a light maintenance and grease after purchasing anyways. But it can be useful.
One issue that I've found with my Daiwa Certate and which no one else seems to have an issue with is the oval design of the arm guard which in my situation always catches the line and is almost impossible to get out. For that reason alone, I'm probably never buying another Daiwa spinning reel until they change it's so easy to screw up an entire fishing session if you don't have backups.
In terms of construction, I would lean a little towards Shimano as I've had one foot break off of a good Daiwa reel but this is purely how I feel about it and there is no empirical evidence that supports this. I've never really had an issue with my Shimano spinning reels really and if you search the Internet for some decent non-US Shimano reels and be patient you can get better deals on new Shimano reels from the dealer/distributor.
Baitcasters, I 100% believe that each reel is different and it depends on your needs and likes. Zillions, Steez EX, Chronarch CI4, Calais, Metaniums, etc... are all extremely different reels to me and I think it really depends on your preference. I like my Steez EX better than the zillions because it's a lot lighter. But I think I like my Chronarch CI4 just as much as any reel because it palms better to me.