Thom,
Welcome to the forums. When you have a fair amount of spare time, install the trial version of Lr. You get 30 days to try before you buy. At that point you can decide which version you prefer. You can still purchase a perpetual license version or go for the monthly subscription model. The CC version does offer some items which are not available to the perpetual license holders yet. At some point, most people expect a version 7 of Lr, at that point the new features added to the subscription model will become available to the perpetual license holders.
A few examples of features available to the CC holders which are not available to the perpetual license holders. Dehaze functions, some Transform effects, something with Lr Mobile (I do not use this so not sure of the details). Also the CC Photo plan includes PhotoShop, so if you currently purchase that separately the subscription plan will likely save you a lot of money.
Ask Adobe, or maybe someone on here still has the link which shows the differences between perpetual and CC.
Tim