I usually build my layouts around 120cm high, although the current small end-to-end layout is just sitting on top of a sideboard in the lounge so my dad can see it when he is sitting down, so around 90cm.
The only thing to consider if you're building your layout closer to eye level is that it can be difficult to reach the rear of the board if it is quite wide, although a small step stool usually solves that problem.
The only thing to consider if you're building your layout closer to eye level is that it can be difficult to reach the rear of the board if it is quite wide, although a small step stool usually solves that problem.