Look to Shure and EV! While i have lots of experience with Shure i have none with the EVs! Shure has done me well for many years!
Stay away from Brands like Audio Technica, Behringer, Voco Pro, etc. If it has a cheap price more than likely it will be a peice of crap!
Yep, Audio Technica is real crap... that's why they use Audio Technica microphones at the Grammy Awards for the last 12 years, the Rock and Roll Hall of Fame induction ceremony for the last 12 years, the Country Music Awards for the last 16, and why BoA and Taylor Swift just opted to use them for their tours. Yep, they make REAL CRAP...
http://www.audio-technica.com/cgi-bin/product_search/current_happenings/current_happenings.pl
There are two components to any wireless microphone:
1. The capsule. This is what captures the sound.
2. The wireless side. This is what gets the captured sound to your rack of equipment.
AT microphones have good capsules. Their entry level equipment - the AT2000 series, are limited on the wireless frequencies to just 10. That's why they're inexpensive - relatively speaking. I have 3 AT 2000 series microphones and I'm going to be selling them - not because they don't work - they work VERY well. But because I'm upgrading ALL my microphones.
I also have an AT3000 series handheld (ATW-T341 Cardoid), and an AT4000 series handheld with a T6100 hyper-cardiod. The T6100 is one of the best microphones I've used - LOTS of frequencies, GREAT flexibility, and a good capsule.
I will say that every company makes somethings that you just have to know it's crap because of the price. I have a VHF Audio Technica set. It works and sounds 'ok'. But it's cheap - cost me about $50 and it came with a battery powered mixer. It's saved my butt once, but outside of a 'I can't get anything UHF to work for some reason' backup - I wouldn't use it.
The Behringer microphone I haven't used before so I have no input on that one. I've heard mixed reviews.
The vocopro units. Wow. Where do I start? There was a time you couldn't GIVE me vocopro and have me use it. But I needed some cheap microphones for karaoke and I picked up one of the NEW UHF-5800 series sets with 4 microphones. To be completely honest, the main drawback to these is they're fixed frequency - meaning if you get interference you can't use that microphone - PERIOD. However, I used all 4 for karoake and I was impressed at the sound quality. Would I rely on them for a 'critical' application? No. But if you need some inexpensive microphones, this ONE unit isn't bad. I'd avoid the others from them though (the UHF-5800 and the 8800 should be ok - but they're FIXED frequency).
If you want a decent 'mid-level' microphone, expect to pay about $500-700 dollars for a new unit.
Entry level 'decent' units go for about $300-$500.
The trick with any equipment is to understand how to use it, the limitations of the equipment, and when to move to something else.
Given the choice, I would limit myself to 5 brands: Audio Technica (2000 series or better), Shure, EV, Sennheiser and AKG.
There are one or two other brands that might be a good fit, but most of these are smaller companies that will cost MORE than these. I have a Galaxy Audio unit for pushing audio that works quite well but I don't know how their microphones are. Sabine makes an interesting unit that works in the 2.4GHz range, but they're pricey.
