Hi g_conaty,
Have a look at
www.airscandic.com
Here's a couple of pics for you:
The A300:
http://www.airliners.net/open.file/191821/L/
The B757:
http://www.airliners.net/open.file/117278/L/
At Manchester at the moment, Scandic have 1 (maybe 2??) A300's based, and a Finnair 757, and as starship says, there is also a Finnair 757 at Newcastle, which is very porbably what you will be flying on.
Reliability-wise, Scandic have a good safety record, and most flights appear to leave on time... I have certainly not observed any mega delays at MAN over the past few months. Operationally (in case you are interested) ATC callsign is Airscan, and the Finnair 757's use this callsign when operating Scandic services.
Have a good time on holiday
Hope it's warmer than it is here anyway!
Cheers
Landing 24R