Compressing images block-wise at low bit rates has at least two major problems: Image quality is degraded and blocking artifacts exist. The latter can be improved by using lapped transforms. Both the LOT and the LBT take about twice the computational complexity, with the LBT being almost negligible more expensive than the LOT.
The LOT was shown to have about a 1/2 dB PSNR improvement over the DCT, for low bit rates. Blocking effects were only minorly alleved. On the other hand, the LBT showed over a 1 dB PSNR improvement for low bit rates, with a readily noticeable reduction of blocking artifacts. Computational complexity is becoming less and less of an issue, and the LBT may be a good alternative to the DCT for low bit rate transmission.