First off, the only good pro wireless is a rack mountable device. The Brace Audio stuff is interesting for guitar although I don't consider it to be very durable, but at the price you can afford to go through a few of them a year. And they don't do vocal mics yet so...
When it comes to quality wireless systems, Shure is still top of the heap. I have sold and installed literally thousands of wireless systems of all makes in all sorts of venues, and by far Shure has been the most reliable and overall the best sounding product. A Beta 58 and a 58 sound like they always do, good but not spectacular. But the radio works themselves are top notch. ULXS and ULXP are very nice, the SLX, well, adequate but pretty cheap feeling considering you would pay more for an SLX than an A-T 3000.
A-T also makes a terrific wireless system, I own over 7 A-T wireless systems, headworn, handhelds, body pack for guitars and have always loved the sound and the reliability. The 3000,4000,5000 series systems all sound really nice. Crisper than the Shure. And the 3000 series is reasonably priced. Way less than Shure.
Also don't discount the Electro Voice RE series. My favorite lead vocal mic of all time for insane gain before feedback is the EV N/D-767 capsule. If you want loud and reliable, E-V is also a great bet. One feature that is very nice on these is the variable analog gain/trim pot accessed via a small screw driver slot on the side of the mic. With the Shure and A-T and many others these days, you get gain sensitivity settings in 3db to 6db digital increments via the internal transmitter's LCD menu display. So you can get close and you can get sorta accurate, but the E-V lets you get the gain set for your voice right on the nuts. Priced between the A-T 3000 and the Shure ULXS.
Sennheiser is ok. I really don't care for the sound of the EW100 series handheld. I'd rather have the A-T, then the EV, the Shure and the Sennheiser would drag in last. Nady and Samson really aren't serious handheld makers since they really aren't leaders in the pro mic world. Beyer and AKG are ok, the AKG is a pain to set-up. They both sound like a better but thin Sennheiser.
Other wireless advice, always use the same brand of alkaline battery. Energizer Industrials are the exact same battery as the normal Energizer batteries. They are called "industrial" to assist in letting employers see if company bought batteries are sneaking out the back door for people's electronic gizmos. Honest to god, only difference. The reason for using the same brand/model of battery is that many of your wireless mics/beltpacks have spring type battery clips. The duracell is actually barely shorter than the energizer. If you use primarily energizers and then try to slip in a duracell after a few years of use, it can become intermittent and cause drop outs because the damned battery isn't making contact. Easy fix, bend the spring clips out.
But either way, stick with one brand, never a problem. Rechargeables are pretty hit and miss. I use Batteries Plus' "extreme" brand and have always had very good luck. Still on my original 8 "AA" and 8 "9V" purchase after 10 years of NIMH use. Not too shabby, but I am a pro sound designer/engineer so I do religeously monitor charging status.