Would you consider $BRK to be a good investment?

Hello, BRK is a holding company that has stake in lots of other companies, In my opinion it is basically an etf , is this a wrong assumption , and would you consider it well diversified? Would you consider it a good time to buy as it has taken a bit of a dip. I’m looking at brk -b because I’m poor , is there any differences between the stock classes that matter tremendously?

Thanks,
– Anxious investor looking to make the right investment for the first time in his life