For our summer vacation, we travelled from Amsterdam to Switzerland. We had first class seats with one layover in Frankfurt. Frankfurt was a mess, the train was sent to a different station, our connecting train was cancelled, we had 5 layovers instead of 1, and had to stand. When we finally got to sit, we had no reserved seats and were split up. On the return trip, similar problem, though with less extra layovers.
A few months later, I went to Essen by train. The ICE stopped at Düsseldorf and the connection to Essen was delayed or I missed it because the UCE was delayed. Still best train experience in Germany that year.
The return from Essen, the train from Essen back to Düsseldorf was cancelled, and the connecting bus would guarantee I'd miss my last ICE and I'd have to spend the night at Düsseldorf. Instead, I paid a lot of money for a taxi to race me there. Got there in time, and at the last minute they sent the ICE to a different platform without clear notification, and I'm pretty sure a lot of people still missed that train. I fortunately noticed some people leaving the platform and informed some others who hadn't noticed.
Trains in Netherland and Switzerland are absolutely perfect, but to get from one to the other you have to go through Germany, and that's a problem.
Iberian gauge allows trains to run faster without losing stability. The more narrow the railway, the cheaper to build, but the less stable for trains crossing hairpin bends for example at a decent velocity.
The climate is also very different, so is not really fair to compare both, but Europe saved a lot of money when building their first railways (and have more problems with ice and snow now for this reason)