Schiit’s older products and lower end products can indeed be grainy or glare. I got rid of my old Magni 3 (not 3+) for those exact reasons. However, I have the Lyr 3 now and it’s almost too rounded and gentle.
Burson has a following on this website – see the Burson thread. Some reported QC issues but I have no personal experience. I’ve been tempted by several of their products.
Topping: Many seemed to like them in the early days when they cost $100. They competed well against Schiit, Objective 2, and other products back then. Over the years they’ve become fairly expensive but still focus on an ultra-clean, ultra-analytical profile in the THX vein. This can be great for pro audio and mastering, but quite fatiguing for everyday use. I’d guess that 2/3rds of the regulars here focus on tube amps, and most of the rest probably choose less edgy, less dry solid state amps. This includes Burson, Schiit, RebelAmp, etc.
Some also complain that Topping games its measurements and focuses on irrelevant measurements (crazy SINAD values) that result in no audible improvements (e.g., correct me if I’m wrong @Resolve, and see this GoldenSound video). Finally, Topping has a hit-or-miss reputation for reliability and customer service. Plus, the early L30 amps blew up and caused damage.
See the threads below for past amp recommendations and discussion: