Bangladesh are mercurial - one day they will put in an exhilarating performance and beat a team like OZ or SA, then the next they put in a shocker against Ireland. If you look at *average* performances over a period of time, BD's average is probably a bit higher than Ireland's. But while Ireland don't deviate too much from their mean, BD do - there's so much more volatility with BD.
Ireland have a limited game - they don't have the raw talent that BD have, they don't have the Ashrafuls or the Tamims who are really nice to watch, but they have a game plan that maximises their strengths:
- good ground fielding in the inner circle to limit singles
- running between the wickets
- bowling intelligently
- stonewalling for the first 30-odd overs at 3-4rpo and then looking to score at 4-6rpo in the next 20
- maintaining their temperament and discipline and not panicking throughout the 50 overs
They haven't been flashy, and often their best hasn't been good enough, but they've performed at that consistent level throughout their matches (aside from against OZ where they had a forgettable match). I think they've gradually gotten better as the tournament's worn on as well.