In what way does it cripple a PC?
I've use it at home for two years now (I buy it for $5. per license per year via Company/Corporate purchase). I do know that when it's updating a person might as well do just about nothing and forget about getting on the internet until it's done updating/patching.
In our work network we use it - tended by a dedicated Server which is governed by Corporate level Servers. It is mandated that we use Trend Micro but we've had little issue with it.
Are you having problem with home version or the version companies use?