The dunes are great. I give it a 4.5 star. The large dunes are much taller than the Mesquite Flat dunes. But the overall area is much smaller than the Mesquite Flat dunes. Plenty of dunes and curves to photograph here. I can't stress it enough that you bring ski goggles just in case you're fortunate enough to get some wind blowing through the silky dunes. It is incredibly beautiful with the sand blowing but incredibly painful with the sand pelting you're eyeballs.
Great hike. The peak is NOT the same as a crater rim hike. This hike is much more strenuous than the rim hike.
As stated below, you start out next to the Racetrack (the Playa) and hike straight up the eastern side of the mountain face. The hike is not for those who are nervous about heights. There are a series of switchbacks up the trail which is fairly defined. Lots of areas with loose rocks/gravel, so watch your footing! At the top there is no defined trail to the southern peak, its a scramble to the top if you want to challenge yourself. You can follow a trail to the north peak which is smaller if you want to extend the trip.
Make sure you bring a lot of water and snacks. Its only roughly a 3 mile hike but it can get very hot and will mostly be dry. There's no coverage except the mountains shadow (we began our hike at 1 and by the time we were heading down, we had plenty of shade from the setting sun). Amazing views of the valley as well as the eastern side of the Sierras. Great way to get away from the crowds at the racetrack.
Ubehebe Peak is NOT Ubehebe Crater. It is found some 20 miles southerly directly west of The Racetrack. The trail climbs 2 miles along old mining trail to a saddle and this part is in quite good shape. After this, it splits. Left has heavy trail markings pointing to it and goes up the side to "Little Ubehebe", a shorter peak to the north along sometimes sketchy terrain can rate a class 2. Right looks more worn and I did not follow very far. It travels around the edge of the peak for a while and may be the continuation of the mine trail to mines in the side of the mountain a little higher up than the saddle. Continuing to Ubehebe Peak from the north is class 3. USGS climbed the south side to place the marker and made no note of the difficulty on that side.