things i've learned shopping for speakers ... watts does not equal quality or performance. I'm not a sound engineer, and I don't know what really qualifies as "good" in a speaker.
when I went shopping for the six i use in my home theater, I took along music which I was familiar with and knew how it should sound. i could play that on the different sets of speakers, and picked those who reproduced the music the best. Price doesn't really determine quality in home audio either, brand determines price and does not represent quality.
the speakers you're looking at are going to be used for PA in terrible acoustic settings (big open square rooms). There's no sense in getting a "hi fi" sound system for a room like that.
you mention this is for your DJ service? How many gigs do you do a week/month? If it's only a few a month, buy yourself a nice pair of home audio speakers, and just use them to do the gigs. If you're not tossing them around and kicking them, they'll hold up just fine, and when you're not on a gig, you'll have a nice sounding set of speakers for using at home. if you're doing a several gigs a week, then buy an expensive pair - look for features like hand-holds built into the cabinets, and heavy duty speaker terminals. also consider smaller PA speakers that can be placed on tripods, useful if you're doing a large room or need to clear obstacles. sure a good set is expensive, but it's a cost of doing business. in the US, business expenses can be written off against your gross income, really reducing your net tax liability.