Wrapping it up...
Given Linksys' virtual domination of the SOHO router retail channel, and the fact that they appear to have delivered what they advertise, i.e. a 4 port 10/100 switched router with built-in IPsec hardware coprocessor based endpoint and no per-user licensing for under $150, I'd say that they're going to be doing some damage to folks like Sonicwall, Watchguard, and others who charge much more for their VPN-endpoint products and have expensive per-user licensing.
So what's the catch? Well, if experience is any guide, and judging from the tone of newsgroup and forum messages, Linksys will have trouble handling the tsunami of support calls that a product like this requires. Setting up a Virtual Private Network between two VP41's should be within the capability of many novice-level users if they carefully follow the information in the User Guide. But establishing a tunnel between a single computer and VP41, or VP41 and your company's firewall, may require knowledge and troubleshooting skills that only folks who have been in the VPN business a long time possess, and Linksys is just starting up the learning curve.
But what the heck, isn't enduring some aggravation worth saving a couple of hundred bucks?