Strawberry seedlings

Hi,
I sowed some strawberry seeds a few weeks ago.

One lot I used a small propagator that came with the seeds.
The rest I sowed in a margarine tub without a lid.

The ones grown in the propagator are tall and thin with small leaves.
The ones grown in the tub are short and stout with bigger leaves.

I am starting to harden them outside during the day but the ones grown without propagation look like sturdier plants.

Is this likely to be the case?

I'll plant them all out and will be interested to see which make the strongest plants.