We had a lovely stay although unfortunately never met Mario! The apartment was clean and we were able to check in very late. It is super central and we never caught the metro once as everything is close by! They let us store our bags after check out as well which was very appreciated. The apartment is very small so if you are going to be in it a lot it may not be ideal however for a couple who were out exploring most of the time it was perfect. We loved Porto and cannot wait to be back!