My budget is <USD500 and I would need the following features:-

- Web Access Management
- 8/16 RJ45 ports
- Ability to reboot the server
- At least 2 x remote users

Can anybody recommend one as I am not sure one is suitable for me? I don't mind a used unit.

Any possibility to increase your budget? That is pretty low for what you are wanting to do.

For a low cost KVM that is also versatile take a look at the dell 2161DS.

You also could go the route of an analog KVM connected to a kvm over ip.

You can do control+alt+del via a KVM, not much more a KVM can do. APC remote management PDUs are a nice choice but again not in your budget. If you are purchasing new hardware you could also get them with onboard IPMI or remote management for a little bit more.