  Automated Machine Learning (AutoML) has greatly advanced applications of
Machine Learning (ML) including model compression, machine translation, and
computer vision. Recommender Systems (RecSys) can be seen as an application of
ML. Yet, AutoML has found little attention in the RecSys community; nor has
RecSys found notable attention in the AutoML community. Only few and relatively
simple Automated Recommender Systems (AutoRecSys) libraries exist that adopt
AutoML techniques. However, these libraries are based on student projects and
do not offer the features and thorough development of AutoML libraries. We set
out to determine how AutoML libraries perform in the scenario of an
inexperienced user who wants to implement a recommender system. We compared the
predictive performance of 60 AutoML, AutoRecSys, ML, and RecSys algorithms from
15 libraries, including a mean predictor baseline, on 14 explicit feedback
RecSys datasets. To simulate the perspective of an inexperienced user, the
algorithms were evaluated with default hyperparameters. We found that AutoML
and AutoRecSys libraries performed best. AutoML libraries performed best for
six of the 14 datasets (43%), but it was not always the same AutoML library
performing best. The single-best library was the AutoRecSys library
Auto-Surprise, which performed best on five datasets (36%). On three datasets
(21%), AutoML libraries performed poorly, and RecSys libraries with default
parameters performed best. Although, while obtaining 50% of all placements in
the top five per dataset, RecSys algorithms fall behind AutoML on average. ML
algorithms generally performed the worst.
