I say that as it looks like Lothian are going after Scotrail passengers rather than First bus on the West Lothian-Edinburgh sector
I spent quite a long time pondering this, as I took an EX2 from Linlithgow to Haymarket today. I was one of about five people on board, on a midday journey. It'll be interesting to see what they're like at peak periods.
First off, the vehicles are fantastic, spacious and comfortable, and the journey, although somewhat slower than the train, feels really quick due to the long non-stop section along the motorway. The only thing that seems problematic is that boarding wheelchairs and pushchairs looks like a complicated palaver, with doors and a lift in the middle. You can't just wheel them on like you can on other buses.
The route Lothian have chosen for this express service is interesting. It's partly dictated by height restrictions, but routing it through Springfield provides the area with a direct link to Edinburgh. Up until now, you'll have had to make your way into town for the train, or to change onto the 38, which is slow and inconvenient. I can imagine a lot of Springfield residents finding a direct door-to-door link an appealing prospect, and it might lure people off trains and out of cars.
In terms of getting people off the 38, I think there's two groups that are clear winners here - first of all, anyone who commutes from Linlithgow to RBS at Gogarburn. It's a hell of a lot faster and more comfortable than the 38, and if I was doing that journey, I'd dump the 38 like a hot brick in favour of a much more comfortable and speedy coach, even if it costs a bit more. The other group standing to benefit would be those travelling free on concession passes - they've tolerated the 38 over the train because it's free for them to use, even though it's much less comfortable and takes much longer. They now have a higher-quality alternative that still doesn't cost anything. The quality might also be good enough to get a few pensioners off the train.
I can't imagine many people commute all the way from Linlithgow to central Edinburgh on the 38, unless they're very, very price-sensitive - the 38 at peak times can take well over an hour and a half to do that journey. So...the majority of Linlithgow to Edinburgh commuters will use the train, but the EX2 is a (slightly) cheaper and still reasonably quick alternative, so it seems more likely to lure people off trains, than getting them off the 38.
It'll certainly be interesting to see how all this pans out. Will it get more people out of cars too? It might. If it grows public transport use overall, it can only be a good thing. The availability of integrated tickets allowing onward travel by tram and Lothian buses is an attractive feature. If I still lived in Linlithgow, I suspect I'd probably make use of it for day trips into Edinburgh, because if I was visiting locations outside the immediate vicinity of Haymarket or Waverley stations, it makes the onward travel easy and good value for money.
I live in Winchburgh, though, where we still have to put up with the snail's pace crawl into Edinburgh on the 38.