• Much easier for the tiler (he doesn't have to tile around something, which is fiddly)
• Much easier for you to replace the toilet later without having to do any re-tiling

timmmay: With the showerdome wouldn't steam build up and cause mould, and require more cleaning? We have a coating on the glass but my wife still wipes it down each day.

Agree wall heaters aren't much good. Under floor heating helps with that a lot. You can get double wired heaters that use 20A instead of 10A that might be better. Heat pump seems excessive for a bathroom.

timmmay: Mine's on top of the tiles. I expect tiling around a toilet would be fiddly. Do make note of where the tiles will go, and get the tile join as far from the toilet as possible otherwise "accidents" can discolor the grout.

Mine was done by Bathroom solutions, who I recommend with a few cavets around how best to work with them. They're a fairly prolific firm in Lower Hutt.

I had a new bathroom put in a year or two ago, some quick thoughts:
 - I like the look of tiles, but under floor heating is essential. Next time I'd get lino/plastic tiles and lose the under floor heating.
 - If you do under floor heating make sure they heat up to very close to the toilet and around the sides. Basically where your feet go.
 - Choosing an under floor heating timer is tricky. The first one was flexible but the temperature varied 5 degrees. The second controls the temperature well but isn't flexible.
 - Get the biggest, best quality towel drying rack you can. I have a control unit (cheap, $40 or so) that turns it on a set power based on a rough schedule. It's primitive, no interface other than beeping, and you can't control times exactly, but it's good enough. I might go digital next time.
 - Overhead "rain head" showers sound cool but in practice I rarely use mine. I spent around $500 on the head, it's about 40cm diameter, it looks like a star trek transported. It uses a huge amount of water and it's really nice on cold days.
 - DESIGN UP FRONT. BS didn't do this well at all. I made my own 3D model using SweetHome 3D (free) which was awesome. Some of the delays were because of decisions that could've been made up front if there was a design.
 - Get a really good extractor fan, multiple speed. We rarely have any steam in the bathroom. The unit I have is entirely in the roof cavity, not a whimpy in line unit.
 - Sealed LED downlights are good.
 - High pressure hot water is great. We had a new cylinder put in the roof cavity, which is cooler in winter, but the new ones are well insulated plus I put a wrap around it too. It made heaps more space in the cupboard.

Questions welcome.