Bowfronts have some issues.
1. The curved front glass can cause distortion a certain viewing angles. I take a TON of pics and it is definitely an issue for me.
2. Some magfloats need to be turned vertical to clean the front glass. Not a big deal, but takes a little getting used to.
3. Some specimen containers will not hang over the front due to the curvature. I use specimen containers ALOT so this is a real pain. The legs for the light fixture keep me from hanging one on the side of the tank.
The bowfronts have a nice footprint for tight areas. The corners that stick way out on a 75 are not there. This was the #1 reason we bought the 72 bow. The tank was going in a high traffic area and we needed the room.
If you want a 180 for livestock reasons, then wait and buy it. A 72 will drastically limit livestock compared to a 180.
BTW, our 72 (non reef ready) was $175 new.