I'm not too sure, out of the three carriers you mention, Ryanair, bmi baby and Jet2 - bmi baby are the least competitive and have offered a 22kg luggage allowance as an attempt to get rid of Jet2 from EMA, something that will not happen.
I know the bmi baby buffs will not like it but EMA has performed much better than projections, over the summer it consistently topped ancillary revenue targets out of all Jet2 UK bases, and the routes offered last summer had the highest load factor percentages after LBA.
Ryanair will always be the true low cost option and Jet2 certainly have lower operating costs than baby. It will be interesting to see what happens over the coming months.