IMO, people tend to hate Line6 more than they deserve.
The DT-25 is a good amp, so is the Amp they made with Bogner.
It's become a meme now though, because everyone's been burnt by the shitty 15watt solid state, 8" speaker, beginner amps.
The bigger Spider amps aren't even that bad, with a larger cone in there, you've got a versatile practice amp, capable of allowing you to demo a bunch of different genre's and styles of playing. That's really helpful to help beginners find their sound.
All that said, boss is moving on on their territory, and they haven't got the same stigma to worry about, despite both amps being basically the same.
There's an element of tribalism in the entry level beginner amp market at the moment, you can see it on this sub. People who own the Katana will trash Line6 and Mustang owners, and vice versa. There's not a huge difference between these products really, everyone just likes to feel justified in their decision, when really all these amps are better than previous generations of beginner amps. I feel sorry for the guys with those Fender Frontman amps though, they're the ones getting shafted.