Yep, it's one of the seedier looking ones but very usefully located for the station as you say and almost always dirt cheap. Never went to floor 6. It has a security guard checking who is entering on the ground floor at night and asking for names, I guess due to issues of prostitution and drug dealing - lovely place Preston is these days!
A couple of online feedback comments suggest undesirables hanging around outside, also people being loud in the courtyard late into the night. Plus the usual comments about slow service or not enough staff to attend to something.
I didn't leave the hotel between arrival early evening (no undesirables visible) and departure the next day. The room I had was on the main road side so no external noise (other than muted sirens) once I fully closed the window and trickle vent. I would give most Premier Inn visits an 8 or 9 out of 10 (nowhere is going to be perfect at the price and locations I am interested in). I would give this one 7 though. The bath / shower was clean but the tiled walls didn't look as though they had been done. The towels and bed-linen were fresh, there was no disturbance from guests other than doors closing, there was some clomping around from the mystery occupants of floor six above me. The mini-fridge wasn't cooling things particularly well where normally they do. The amount of crumbs down the side of the cushions on the bucket chairs was substantial though. Always a good check for housekeeping standards - under the bed, corners and under cushions!
If a hotel needs a security guard I probably wouldn't stay there, even if it is really cheap. I guess having key card entry to the building after a certain time wouldn't entirely replicate the benefits of the security guard.
That tends to be my line for pubs, if they are paying money for a bouncer they are probably expecting trouble, so avoid. I wouldn't take the same view on a hotel (or station, supermarket or office block though). Somebody mentioned earlier the first floor reception arrangement and all-night security guard at the Piccadilly Gardens Travelodge, but I wouldn't stay there because Piccadilly Gardens is an absolute hole at any time of day. Far easier to be just outside the main area.