Depends on the management. I used to work for a very large company that often bought up smaller companies to gain their IP/technology/market share, then ruined them. Not necessarily through any sort of malice, but because the bureaucracy and administration large companies bring to bear is expensive as hell and extremely time-consuming. It's like giving crippling arthritis and arteriosclerosis to a 21 year old sports superstar. Thing is, the upstart often doesn't know what's going to happen and the marriage comes with a huge dowry for the founders, so it seems like a great idea.
But, it doesn't have to work out that way. Large companies also have a lot of inertia in the form of financial and marketing resources, so they can afford to do things that small companies can't. I mean, look at Microsoft. They can ship pure garbage in mass quantities and get away with it for years on end, and still come out ahead of the game and ready to take another hit straight to the gonads.
Line 6 has made some interesting products, as has Yamaha, who has great resources. It could be a marriage made in heaven. Or, it could be the end of Line 6.