resampling - what is better: up- or downsampling?

I want to compare two signals or curves.

Unfortunately they have different sample rates. The first one is sampled at 30 Hz, the second at 2000 Hz. Matlab has the function 'resample' and I thought, this would make comparison much easier.

My question is: Is it wiser to downsample the second curve or to upsample the first one?

Edit: I did as I was told. In the picture on the left are the original curves. The curves on the right are resampled. Top right is upsampled, bottom right is downsampled.

I know the curves are of different length, when resampled. However, the second signal will get cropped to the first signals length.