My husband and I, and another couple, booked this apartment for 16-22 September 2010. We were in Edinburgh for a few days of relaxing/sightseeing before heading to London and Paris.
The interior of this apartment was just as it appears in the photos - a charming place. The only things I'd mention about the interior are that the walls between the rooms are thin (so not a lot of privacy if you're traveling with other people), also the mattress in the second bedroom wasn't as nice/comfortable as the one in the larger bedroom.

The location is not far off of the Royal Mile (good), but there seemed to be several clubs/pubs/ youth hostels? on the street and the streets just around the apartment (not so good for us --we're boring and like to sleep at night =).

Unfortunately, when we booked the apartment we did not realize that it is right next door to a club on Niddry street (called The Caves - looks like a cool subterranean music venue - evidently has great acoustics). We, again unfortunately, also arrived in Edinburgh during Freshers' Week - so there were events going on at all of the area clubs, pubs, bars...

The first night we were there, we were jet-lagged and there were no events going on next door. The bedroom windows in this apartment are at the street level, so we did hear some noise that night, but nevertheless, we slept some. The next night (a Friday) there was an event going on at the club next door and we didn't sleep at all. I'm not a light sleeper, but it was very loud. The music from The Caves vibrated through the stone walls of the bedroom until early in the morning, and area club-goers loitered outside of our windows talking and laughing until the sun came up...

That was a frustrating experience given the limited amount of time we had to sightsee in Edinburgh (we ended up sleeping half the day away to catch up on zzz's).

But I have to praise the attentive management of Edinburgh Self Catering. We communicated our sleepless situation to Mr. Ford and he was able to arrange an apartment exchange for us that very day (Saturday). We moved to Parliament Sq. 2 (awesome place- my review is forthcoming), and didn't have any more problems with noise.

The location of Niddry St 3 isn't exactly bad, I guess. It just depends on what you want out of a holiday. I'd recommend Niddry St 3 for a young couple or a group of friends who are interested in nightlife in Edinburgh's Old Town.

It's possible that the Niddry St 3 apartment could be a bit quieter when it's not Freshers' Week and there are no events going on, but if you're an older couple, a family with children, or, like us, a younger couple interested in a relaxing/sightseeing holiday, then I'd suggest Parliament Sq. 1 or 2 instead...