WorldMark has three resorts in Las Vegas. WorldMark Blvd is on Las Vegas Blvd (the Strip) about 4 miles south of Mandalay Bay. The Grandview is about 3 miles further south on Las Vegas Blvd. WorldMark Spencer St is on Spencer Street, just off of Flamingo about 2 miles east of Las Vegas Blvd. WorldMark Tropicana is on Tropicana, about 2 miles west of Las Vegas Blvd.
The Worlmark Blvd resort has the most amenities, with three swimming pools, a lazy river, 4 or more spas and a parking garage in each of the buildings. It is our first choice of the three WorldMarks when we visit Las Vegas. It was built from the ground up as a WorldMark resort. Even though it is on Las Vegas Blvd it wouldn't be considered to be on the strip.
The other two WorldMark Las Vegas resorts are converted apartment buildings. Spencer St is ok, but it is definitely an older facility. We haven't stayed at the Tropicana resort so I can't say how it is. We have visited the Tropicana resort and viewed the buildings and the grounds and I would say it has a much nicer overall appearance than Spencer St.
The Grandview is also a nice resort, we have stayed there 2 or 3 times. While it is the farthest out of the 4 resorts mentioned, the fact that the South Point Casino is next door is a plus. In addition to it's more friendly casino (in my opinion anyway) the SouthPoint has several very good and relatively inexpensive restaurants.
Of the 4 resorts, I would pick WorldMark Blvd first, with the Grandview a close second. Since you are looking at a two bedroom unit, bear in mind that the Grandview units are two bedroom lockoffs. You really get two complete one bedroom units, not a true two bedroom. We've always had only two people in a one bedroom so that was not an issue for us.