Both are capable of doing the job you describe.
Backing up a bit, first consider your use case. The decision of what recorder to use should start with how you intend to use it. Neither of those recorders, nor most others used by concert tapers feature over-dubbing capability. You will be able to record yourself playing and singing along, but that's pretty much it. If you want to record those two parts separately, add additional parts, double-track things or whatever in combination with what you previously recorded, these recorders are not what you want. Instead, seek out a multi-tracker machine that capable of over-dubbing. They come in all sizes from smaller to larger than those two recorders.
The two recorders you mention are/were good 'prosumer' quality early-generation digital flash-memory stereo recorders featuring balanced XLR inputs. Yet they are also rather dated at this point. Generally, the cost-benefit ratio for digital recorders has improved dramatically since and unless you've found a particularly attractive deal on them, it may make more sense to look at something newer.
Some important practical aspects are things like what memory the recorder uses. FR2-LE uses Compact Flash as I recall, which is no longer used in new devices, so may be harder and more costly to source (or not, I've not looked). PMD-661 uses SD cards (SDHC I think?), so easier to source, just wont be able to use larger capacity SD cards than it is capable of handling. You can typically always use a smaller capacity card.
Pretty sure both supply 48V phantom power, which is generally required to power a condenser mic. To use a condenser mic into a recorder that does not provide phantom power, you will need something else to supply that, such as a phantom power supply or external preamp that provides phantom, and additional patch cables to connect everything up. It gets complicated. Often best to keep it simple and easier to setup and manage with just microphones and recorder.
Dynamic mics, including ribbons, do not use phantom power (some ribbons will be damaged by it), but tend to be less sensitive than condenser mics, meaning they will require more gain to achieve the same recording level. In that case, some lesser quality preamps such as some of what are built in to recorders can get noisy when cranked up to compensate. Not sure about the internal preamps of those two recorders as I've not used them myself, but most inexpensive modern recorders and multi-trackers will tend to have cleaner preamps and lower noise-floors than recorders produced 15 or more years ago.