1st, the back area around the frame usually hard to clean because the back portion is not flat piece and has lots of gaps.
2nd, the frames edges are very sharp and poses a danger for cabinets opening at head height. even for lower frame i can scratch my legs if i forgot to keep clear.
New frames have somehow solved this issue by either using a Male & Female frame to ensure smoother edges, or add a rubber piece on the edges. the former one is the nicer way but cost alot more as manufacturer cannot produce the frame by simply cutting a long piece to their requirements.