I've just been playing this update.
The Atlas RR track available to those on the TPP has seemingly taken some of the structural design aesthetics from WO Fusion's Temtesh bay - think of a track made by the same people who built the millennium stadium , and put them in a Sol 2 type of context, but this is racing around a structure.
It has the dreaded semi transparent track look of the FURY tracks, but ATM they are a slightly plain, untextured opaque Red, so the visual confusion you get with the Fury tracks is thankfully not a problem here...as yet.
The track seems very narrow compared to the others, much like Sol 2 in lot of places, there are two jumps. or track drop off's, both small, but there is a problem with one, and that's every time you go over it, it's like something has grabbed the back of your craft and slowed it right down....think of a plane landing on a aircraft carrier.

When I first fired up this track I opted for TT using F3000 craft.... what happened next was it loaded me into what I could only describe as being at around zone 70 speed, and the track was wavering up and down like a rubber band...unplayable...thankfully after going back to the menu and restarting things ran normally.

The other new track for those on the TPP is FURY RR, this is set in a earthquake ravaged city, and there are broken overpasses to race over.
There is one point where you run over about 5-6 broken sections of track in quick succession, you can get over most of them without being impeded, but the last couple can slow you down, by how much varies, as I haven't as yet found a rhyme or reason to it, this portion of track also effects the A.I., as I noticed it broke up the field, that up to that point were in a procession.
Not a very challenging track except for one chicane, and I think my problems with that is down to the sole racing POV which I would never use normally.

Niagara looks good, and the track is surprisingly wide, it's the widest track I've seen in a AG racer.
One problem with it is ATM is that unfortunately I found it a boring track to race on, even though it is long [think the long tracks on WO Fusion ]
I honest to God got a flash back to N64 days play F-Zero X on my first lap of this track.
Maybe R8 are intending to have a few easy tracks in the game to break people in, sort of like a Anulpha Pass in WO HD, and Niagara is FF similar type of track.
If that is so, then Niagara has certainly filled that design brief.