Just wanted to share our (AS15703, True B.V.) experience as a hosting provider with enabling RPKI invalid filtering (invalid == reject). We've secured (most of) our routes since 2014 with ROAs but last Tuesday we have deployed filters which reject RPKI invalid routes. We have had two tickets regarding users in one certain RPKI invalid prefix not being able to reach our network, but those people quickly understood that this wasn't our problem but a problem with their hosting partner. They took it up with their hosting partner and it was fixed within a day. Overal, I would certainly recommend filtering RPKI invalids (and create ROAs for your prefixes!!) to prevent hijacks.