My 4000D has 1152x864 24-bit Workbench via Picasso IV, Deneb USB with card reader and 10/100 networking, 18GB hard drive (to be 60GB SSD sometime soon,) CyberStorm MKIII 50MHz 68060 with 144MB RAM (128MB on the accelerator and 16MB on the motherboard) which will be replaced as soon as I get my CyberStorm PPC repaired. I have been able to configure Miami Deluxe to VPN into my managed networks. I use RDesktop to work on servers and remote workstations, an ssh2 client to run my Solaris servers, and YAM for my personal email. I don't browse the web on this machine due to the lack of a modern web browser, though IBrowse is often good enough for basic stuff. Using smbfs I have a shares on my Windows workstation and NAS mounted to provide protected file storage where necessary. It has an IDE DVD R/W drive attached to the SCSI controller, though I don't use it that often.
I use this as much as I can. I don't often sit at my desk, so I use my laptop more frequently, but it's there and usable. I cannot really answer whether your investment opportunity is worth it as I'd prefer a working system to start for cash. YMMV.