If you're downtown, you will have easy access to, well, all corners of the city, basically. If you live in Mill Woods, you're not taking the LRT to get to Southgate or the UofA, even if those technically are connected by LRT. I fail to see what is unique to Valley Line West that will "finally" make ditching the car feasible in Edmonton in a way that Valley Line SE, the Capital Line, or Metro Line haven't done. It'll be a boon for those on/near the line, or Downtown, and will likely be used if you're going from, say, Stadium to WEM, but probably not if you're going from Century Park to WEM. For people in the suburbs, even if there's an LRT line nearby, the likelihood it'll actually connect you to all of your daily needs is lower unless you live Downtown and you have tremendous LRT access. Once the Metro Line goes to Castle Downs, you still won't be able to get to where most in the area go for shopping, Skyview, by LRT, because of foolish routing choices.
Regarding travel times, the 900X was faster before the LRT construction. Valley Line SE does not promise a faster ride than the bus from DT to Mill Woods and although I haven't seen anything similar for the west line, because it is being built similarly, I wouldn't be surprised if it's about the same speed, just higher capacity and grade-separated. These low floor trams are not the highly efficient trains we're used to on the Capital Line. The Valley Line, as slick as it looks, feels like it's going to be less efficient once it finally opens. More stopping, higher likelihood of car crashes, lacking true signal priority, and at-grade through downtown (we will regret this I'm sure... look at Calgary).