Shure SLX24/SM58

Well the thing to like most is that it's wireless! Your freedom of movement is no longer restricted by your cables! What's not to like? Well, if you've been dealing with wireless systems for awhile you know that when you start adding more and more wireless recievers together you encounter all sorts of problems. Shure did a fantastic job with this series of mic/transmitter/recievers and they still hold their own and function very well, but you have to know just how many you can use in certain set frequency groups before you start having major problems. This is no big deal really, Shure has great online support for these systems and all the info you could possibly need is there and easily obtained!
Keep in mind Shure is a legendary name in the live and studio audio world so you will pay the tax for that but their gear is top notch. These wireless systems perform great as long as you take the time and have the patience to set them up properly you will be totally satisfied. The main issues that you will have will occur when you are using 6-14 units simultaniously. At this point it becomes very difficult to select clear channels for all your different transmitter/recievers, also in certain frequency ranges Shure recommends only using a certain number of transmitter/recievers. It is VERY important that you research these issues before you buy a whole lot of these, if you're just using one then you've got no worries.
Shure does sell an antenna combiner which not only reduces your footprint but also provides a little bit of boost to the individual transmitter/recievers signal and is ultimately VERY helpful.
Many different companies offer wireless options but you can count on Shure to provide you with good quality equipment. All the headaches of wireless aside, Shure's equipment delivers!
When wireless equipment fails or looses signal it's...well it's just really bad. I certainly cannot promise you perfect opperation all the time with this rig, however I can say that with a properly set up Shure rig the sound quality is great! You really won't even notice that it's not hard-wired!
Overall, based on all the different companies wireless rigs that I've used, I trust Shure's stuff the most. If you've got the money then go with Shure, if you're a bit short just save a little extra and buy Shure.

I use it since it was purchased, used, in November 2010.
I had already tested a wired SM58, I knew the microphone and I was looking the same, HF version.
The SLX is really nickel, no breath, no drop, nothing.
I use it in rehearsals, my singer also uses an SM58, but wired, and the difference is inaudible on our sound system anyway.
On the concert sound systems, same, same wireless finally wired.
I used it right in Lyon, and I had no interference.
If the SM58 is no longer appropriate, the capsule is interchangeable with other Shure ...
I touched € 350, U.S., postage included, with the microphone, the receiver and transmitter guitar.
At this price, it is unbeatable especially given the quality of the machine.
It takes about 10 am with rechargeable batteries 2.5 Ah.
I would do the selection without hesitation!