The High Roller is pretty much just a very large ferris wheel but you do get the beautiful views and bright lights of Vegas.
It is a bit pricey, twenty-something to high thirties depending on what time of day you go. We were fortunate to get discounted tickets for it while attending Jersey Boys. Make sure to look at Tix4Tonight or some discount tickets location. We were able to get our tickets for $20, regular price I think $28.
The lines were quick enough and fortunately the cars weren't too packed. We were all able to get standing window spots (I think there were about 20-25 in our car).
Also, we went at about 4:30pm. It worked out perfectly because we were able to still see daylight when we got on and were able to see the mountains and terrain but by the time we got to the top it was dark and we were able to see the lights of Vegas at its brightest.
Worth doing once . Just make sure to try and find discounted tickets!