Which VPN Server Hardware is Best for Accessing from Mac Clients

We are an all-Mac shop (well, actually, a mostly-Mac shop - we have some Linux servers running behind the scenes). We do web applications development and our files and source code is all hosted in-house. Our Mac-toting consultants would like to connect to the office to access files (AFP to shared volumes), update source code (subversion over HTTP/HTTPS), and demo software (HTTP through a browser) when they are on a client site. Traffic will be light. We are a small company (and cheap), and do not expect more than 3 or 4 people to be connected concurrently. However, we need the solution to be reliable. Many of our clients and consultants are abroad. Which VPN Server Hardware is best for this scenario? I would prefer something that uses standard protocols - I understand that L2TP, PPTP and Cisco IPsec are built in to the OS - so something that uses these protocols will be ideal. (I have seen quite a few VPN solutions that have horrible, buggy, and badly supported client software). An added bonus would be support for iPads as well. Naturally, I would like it to not be too expensive (I told you we are cheap), though what I really mean is that I am far more willing to pay for reliability and built-in support, than for features I do not need.