One thing to remember- is that there is significant overlap (about 90%) in the frequency range output by both the human voice, and any scale length of ukulele, and as such, and 'vocal' mic will work fine as an 'instrument' mic for ukulele. (I have personally confirmed this myself with a audio spectrum analyzer).
Unless you have a situation that is the 'exception', any marketing-speak on the label could be regarded as hype.
Having said that, for a vocal dynamic mic I prefer the Electrovoice ND/767a (~$129 USD), which tends to have a warmer sound than the Shure SM57/58 and their 'Beta' flavors, and being that I am 'blessed' with a limited baritone singing voice, this mic tends to cut through a dense wall of sound easily, without requiring lots of EQ when playing with a larger group, and when playing solo, it tends to carry the sound in a more 'penetrating' way to the speakers than the Shure counterparts.
As per what I said above, it also works great to amplify the ukulele in the case of playing an instrumental set. The ND/767a also rejects feedback a bit better than the Shure mics, and is a bit more sensitive then they are, both on paper (in the maths) and in use on stage.
Also, whatever mic you use, you can mitigate/enhance it's flaws/functions with a decent preamp. Some inexpensive options for a TUBE mic preamp that I have used to good effect are the ART Tube MP (and others in this series), and it's slightly cheaper copy - the Behringer MIC-200. They both supply phantom power if you are using a condenser mic, as well as act as a direct box, and the vacuum tube *may* sound a bit warmer and less harsh than using a solid-state preamp. You can run the output of any of these preamps into a guitar amp or PA system without any problems as you can adjust the output impedance to match the equipment it is going to plug into via the 'output level' control.
drbekken, if you already have a Shure mic, but find the sound lacking, you can get one of these preamps I mentioned here for ~$50 USD new @ Amazon, B&H Photo and many other sellers, and see how it improves the sound for you. These are also frequently available used on eBay for cheap for when folks eventually upgrade to a fancy tube preamp, like a Manley, Focusrite or Grace Design model.
These tube mic preamps tend to take ANY mic and make it 'hotter' (i.e., more sensitive), but you will need to play around with the settings and mic placement a little, in order to get the sound that you like the most. The main point is that if your mic is lacking in tone or sensitivity, these preamps can really help a lot.
I've personally use them for years as a panacea for many live and recorded 'sound' and impdeance-matching problems.