Hi there

I took the Stansted/Las Vegas trip shortly after it started earlier this year, and overall pretty satisfied:

• Like other Low Cost Carriers, you get what you pay for (older style Bus Class seats but a much cheaper fare) delivered to consistent quality standards
  
• On board service just fine
  
• Stansted massively better than Heathrow; at Las Vegas they were just getting started so didn't have a lounge set up

For me (as a United 1K, mostly on my own dime) its still better to buy economy and upgrade with SWUs if that makes sense from a total trip perspective, but I think the new generation low cost Bus Class carriers (Maxjet/EOS/Silverjet) are here to stay and will be increasingly formidable.

Happy travels however you go!