It always comes down to how you value your time, money and experiences, and your capabilities.
Is the West Rim notable? Yes, compared to what most folks have back home it's probably amazing. But it's not the South Rim. Tour? Let's be honest, most travelers are happy with a kick-the-tires experience -- arrive, peer over the edge, snap some shots, hit the gift shop, peer over the edge a few more times, check out the historic/interpretive offerings, depart. That can be accomplished on a day trip.
Now if you're not averse to driving, if you're cool with missing a night (or two) in Vegas, then overnighting opens up more options, the most important of which is that you're on your own schedule, not that of a tour company and the 45 other folks on the tour with you, and you can linger or move along as you please, experience as you please.
My personal opinion: If a person gets one shot in his/her life, and that one shot is time in Vegas or time at the Grand Canyon (Zion, Bryce, wherever), the neon loses. Thankfully Vegas and the spectacular desert southwest can be combined.