I guess it all depends on how accurate you need your data. All shots taken should all be "relative" to each other and possibly only the "real world" coordinates would be off. In theory anyway. The hand-helds I have compared to were used for cell tower locations where your X,Y positional tollerance is 50' +_ and Z tollerance is 20'+_. Garmin has a unit called the Colorado400T that uses the WAAS technology that gives results within 3 feet. This unit lists for $599.99.
The cost rises rather steeply when you get into the "survey accuracy" instruments that are supposed to yield subcentimeter accuracy. Then you are talking megabucks.
Thing to do is decide on your accuracy requirements and then surf the manufacturer's web sites, They all have a :cotact us" link, co bug the crap out of them until you find what you want. Then ask them for a discount. They like that.
Sometimes they will even do it.