In general terms I find the European venues and smaller American or European hotels far more pleasurable, simpler and cheaper to deal with.
The unionized American venues are very expensive and can be a nightmare to deal with. Want coffee in a room for visitors? Sure. It'll be $200 for a gallon. Want a light turned off above a booth? No problem, it'll cost $350 for a union electrician to go to the breaker panel and quite-literally flip a switch. Need to bring some boxes on a dolly to a booth? Can't do it. Once you enter their domain union members need to handle even the most basic of jobs.
In general terms, large venues are expensive, union or not. The union part just skews the cost curve because of how bloated and unreasonable things can become. Add to that insurance, guarantees and other fixed costs and you have a solid formula for high prices for attendees. And, if you are after a venue such as the LV Convention Center, well you'll have to sign a contract and pay a large chunk of money upfront a year ahead of your event.
Then there's the issue that someone alluded to: What do you actually get out of conferences. There are some where you might just meet a person or learn about a technology that is a game changer for whatever it is you are doing. That's priceless and always worth the cost of admission. More often than not, at least in my experience, conferences are very disruptive and do more harm than good. Why?
If you are an exhibitor very soon conferences become these artificial and unreasonable deadlines that almost require you to make announcements. This means that mad scrambles happen around them to get to that point. This can disrupt a company for weeks, both before and after a conference.
As an attendee, you might also delay acting on purchases in order to see the above-mentioned announcements at the conference. The problem is that most conference announcements are vaporware --requiring months of additional work to be real products. By waiting for the next shiny thing you delay your process. And then, of course, there's the huge disruption of sending a whole team to a conference for three to five days --or even more if it requires traveling out of your country.
For a large class of things I have personally found that the quality and depth of information available on the internet is significantly better than what you can get at a conference. I have avoided conferences for three years now, and, I must say, I have learned a lot more, been more productive and made better decisions because of it.