Yep, there is AC.rms, AV+DC.rms, Vpp (or Vpk-pk), and STD.
Btw., the noise levels of that Siglent and Rigol as depicted above are "almost the same" (20% diff in the noise is negligible). Thus the question is how the 8bit vs 12bit comparison would apply here..
It depends. Since SDS1104X-E has 500µV/div real range, for small signal it would be pretty much the same.
SDS2000X+ shown above has much less noise than DHO800, despite being 8 bit. At 50Ω it would be even better (but so would DHO800 with external terminator).
So like I said many times before, it is not that simple.
All in all, Rigol finally made an inexpensive scope with quite competitive noise levels. It is not as good as good 12 bit scopes, and not even as good as best 8bit ones, but good nevertheless. Noise is no longer a problem. Especially for the price bracket.
It would be interesting to see how well DHO4000 fares.