Disgusting
The worst hotel I've ever stayed at. I usually laugh at some of the reviews you read, where people book a budget hotel and then write a bad review because it doesn't offer superfluous services/facilities or because the decoration is basic or the furniture outdated. Therefore, I'm a bit sceptical and try to read between the lines. When visiting a city, as I spend all day out and about, I prefer to save money on the hotel and spend it eating out or shopping or on attractions or whatever. Consequently, all I need from the hotel is a clean place to sleep, have a shower and leave my stuff, I'm really not too fussy. 
Before booking the Carter, I read several reviews and thought it would meet the criteria. People are usually more critical and demanding than I am, and despite that, reviews in general were OK. Although the location is great and initially it seems like a good price (it turns out it's actually expensive for what you get), it's not worth it. A terrible pungent smell down the corridor and all the way into the room, which was disgusting. The carpet was filthy, covered with what previous guests had left, definitely hadn't been vacuumed for months, and as if all that wasn't enough, just a few minutes after entering the room we saw a DEAD MOUSE lying on the floor. We left.
I've stayed at many budget hotels in different places and of course they're usually basic, but adequate taking into account what I'd paid. I'd never seen anything like this. If you want to stay somewhere central, you need to pay out a bit more, otherwise you risk ending up at a place that's a public health hazard. If you're on a tight budget, you're better off staying somewhere a bit further away from the centre, as public transport works well and taxis aren't even that expensive.