Hi there, I'm from France, which is one of the only countries I know of where these are fairly common. Obviously, if you want to have another toilet and there is no other way to hook up the plumbing, a macerating toilet might be the only option. If there is another option, however, I would definitely take it. Macerating toilets are much less forgiving than regular toilets. A guest throws in a tampon? Say goodbye to the toilet; you're going to need to buy a new one. (I am speaking, unfortunately, from experience.) Also (I'm assuming you're in the US), there isn't much in the way of knowledgeable technicians if you ever do have a problem that can be repaired. Which, again, is less likely than with a regular toilet. Because there is a motor and a blade involved, any damage is often irreversible. Then, of course, there are the aesthetics. The sound of the flush and the general appearance are that of an airplane toilet. Finally, because the toilet itself does not contain much water, these toilets tend to develop (and retain) odors much more quickly than conventional toilets.

Is a macerating toilet one that has a pump that minces the waste up so it can go into a smaller soil pipe rather than directly into the sewer? If so, we had something like that in our old basement. The main problem was the noise. When it needed servicing it also smelled bad - and then you have the expense of the regular services.

"Is a macerating toilet one that has a pump that minces the waste up so it can go into a smaller soil pipe rather than directly into the sewer?"

Yes.

The OP would do well to install appropriate plumbing to handle a regular toilet in their new attic bathroom - They'll be better off in the long run.

We'd love one for the same reason, but see if this article from TreeHugger doesn't talk you out of it: http://www.treehugger.com/files/2005/03/the_hot_poop_on.php

What about an Incinolet? My friend had one in her beach house and it worked great.

Don't do it! If you have your heart set on another bathroom, and it really isn't possible, buy a different house. Or talk to an architect (they often have ideas for layout that mere mortals would not consider). And think about it - if the house is really old, it probably needs new plumbing anyway, so just do it all right. Don't bodge in a bathroom with a saniflo to save money, then have to redo half the plumbing in 2 years and the other half 3 years after that.

On the saniflo itself...

(1) From experience (only renting in France) they are terrible. They smell. They are loud. They break if you flush anything other than human waste down them (no TP - you have to have a bidet). They break if you only flush human waste.

(2) No one in Boston will want a bathroom with funky plumbing. Adding the bath will not be good for your resale value - it will likely hurt it if it smells funky. And you may have trouble getting permits/inspections depending on exactly where you live. Plumbing code in MA is pretty tough and specific. Are they even approved here?

(3) All plumbing breaks at weird times - nights, weekends, holidays. You want something every plumber in the 617 area code has fixed 100 times, because you will have to call 10 people to find someone who'll come on Thanksgiving weekend. You don't want something only a few people can fix.

(4) I joked to my British husband about getting on (as in, I said 'if you don't hurry up in there we'll have to put in another bathroom and get a saniflo'), and he a replied back - 'we're better off burning down the house. Apparently it is a common joke:

http://www.diyfaq.org.uk/humour.html#saniflo

Ew. You're better off with chamber pots.

OP here!

Wow, you guys really hate macerating toilets! I've definitely been dissuaded from using one in our future bathroom.

Initially, I was interested in them because they sounded so economical (fewer installation costs, less ripping up of stuff in our old house with plaster walls), but a smelly bathroom and lots of plumbing issues aren't something I can live with.

We'll definitely be consulting a plumber and/or architect to see what we can do about adding another bathroom with regular plumbing, though.

maddux: incinolets sound scarier than macerating toilets!

Siobhan: we're actually buying in the Cleveland area, but most of your observations about Bostonites apply here.

Thanks for your great comments, everyone!

We had one of these in our holiday home in France and I don't think they're quite as bad as everyone's saying. You can use loo roll in them, but only the cheapest, thinnest stuff and that is the ONLY thing you can put down there (not even hair!). But as long as you do that, they're mainly fine.
I think it depends. I would never put on in a bathroom that would be used by a lot of guests or children, but in a master bath it could work fine.
BUT they are noisy when they flush and then noisy intermittently for no reason every now and then, which would count against having them in a master bath!
In all honesty, I do think that right now whilst you're having loads of work done on the property is probably the best time to do the proper plumbing. But thought I'd share my experience as well.

Its my only option in a basement.. So I'll be installing one anyway.

Who puts hair in the toilet????

We have the Saniflow:Sanibest Toilet/Pump installed in our basement. Our laundry machine was relocated to the basement by the previous owner, but no pump was installed making it impossible to drain the water. The Sanibest system does make a grinding noise for a few seconds when flushed, but it really isn't as bad as people are saying. I think the newer systems are a lot better than what people have experienced. We've had this installed for 2 years without any problems and we installed it ourselves. It was actually really easy to install and since it isn't inside the wall, if the pump ever breaks or needs servicing you can easily access it. (10 yr warranty) I definitely recommend getting the Sanibest system though, as it does handle tampons, and can handle the drainage from other bathroom items such as the sink.