For most people I don't think it makes a big difference, its really just a matter of personal preference. Its easier to set a Mac up to run Windows than a PC to run Mac OS. On the other hand Macs are far more expensive. They look cool if that matters to you (I couldn't care less). If your lab runs one or the other, that may be a good choice to avoid any possible compatibility issues.
Personally, I do not like Macs. I think they are fantastic for people who are not huge computer geeks - you get great stability now that the OS is Linux based, there are nowhere near the security issues, etc.. However, I am a gigantic geek and for the most part, that = PC. Part of Mac stability and security comes from greater limitations - great for people who aren't sure how things work, not so good for those of us who know how to change things without breaking it. If I can't rip a computer apart, swap parts, alter my system settings, etc. I get irritated. Heck, I don't even buy retail PCs anymore because they always come with at least a few parts I don't like and to change those I have to change something else and it just ends up being a mess. I am in a very technology-heavy lab where I have to do a fair bit of software programming and similar work - almost all the software I use for this runs on Windows only, so there is no point in me paying twice as much for a Mac if I'm just going to boot into Windows every time anyways. That said, I am probably the exception rather than the rule so I recognize that for most people it is a fine choice.
Not sure if that helps any. When in doubt, you can boot into Windows with a Mac so don't worry too much about compatibility in that direction. Whether the price is worth it is an individual call. Whether a Mac would suit your needs really depends on the kind of work you do.