F on Air China is just regional Business for regional routes.

For SHA-BJS for example they only offer F & Y only on most flights (see below!), but in reality F is just a regional J class.

However, that route as an example they use pretty much everything they have. Picking out this Saturday alone I see 733, 333, 321, 757 & 767 (these two codeshares on Shanghai Airlines) 777, 340, and to round things off a 747 for the last flight of the day!

The 340, 777, 747 have Y, C & F so I presume are geared to international spec, so it might be C on one of these is better than F on the smaller craft - or if the same price, try going for F on one of the above.

I've only done J & Y on international CA so not qualified to advise on quality of domestic!

A 32M is one of their Airbus 321 variations.

Look here for most accurate seat maps: http://www.airchina.co.uk/en/managemytrip/seatmaps.html