I use a P-4 shredder, also from Fellowes, that cost a couple of hundred bucks, that replaced a burnt out P-2 shredder I got for $30 from Staples. I am considering going to a higher capacity P-5 if I can find one at a reasonable price on eBay, mainly for the extra shredding capacity and the hopper feeder than any additional security it provides.
How seriously do I take my disposal security in my home? Well, I'm not a target, and there are other higher value targets with less security, so why would they go after me. I shred any mail or paperwork I don't wish to keep physical copies of, but it sits in the "to be shredded" basket near the shredder for a good six months before I get around to it. There's an oppportunity there, if I were a target. And the "to be shredded" basket will contain bills from my medical insurance provider, phone bills, ISP bills, electricity bills, cheques I've deposited, grocery receipts.
Whilst I practice good op-sec within my house -- no paperwork leaves without being shredded, tightened network security, VLANs for suspicious devices, locked down networks, and 2FA where appropriate -- I'm not a target and I have very little reason to be a target, so I don't need an onerously heavy shield. I'm cautious, not paranoid.
You need to evaluate your disposal security within the context of "what is convenient" rather than "what is best."
And I have found that most corporate security, especially in the biometric arena, is sub-par, usually because of the human component doing the enrolling. I am not saying it isn't workable, but that there is a vast landscape between people's perceived utility/functionality of the security and the actual security envelope it provides. Fortunately for me, security is very difficult to get right.