You could also consider where both bands came from, and what bands evolved from them.
Foo Fighters aren’t bad at all, but I’d prefer to hear Temple of the Dog (never listened to Mother Love Bone).
Foo Fighters are good. I think that Cobain was clearly the main influence for Nirvana and that Grohl was sort of a largely untapped resource that probably would have asserted itself if Cobain hadn’t died. But with Cobain gone, Grohl was able to show his full abilities. But I do think that Cobain at least somewhat influenced Grohl in positive ways.
Temple of the Dog to me was more Chris Cornell than anything. Yes, Pearl Jam members contributed to the sound and co-wrote some of the music but Cornell did more songwriting than the rest combined on that album.
Say Hello to Heaven, Wooden Jesus, and Times of Trouble (my favorite) are better songs in my opinion, but Hunger Strike was the one that got all of the airplay because it was more digestible to the general public. An interesting thing to note is that it was sort of Cornell’s attempt toward making a few of his “pop”-ish songs that appealed to the radio listening audience and it just so happened that Vedder was lead vocalist on that song.
I have one of Mother Love Bones albums and I’m not entirely fond of it. I think Andrew Wood was trying too hard to be the Alternative’s version of David Bowie a la Lady Stardust. That guy was clearly a conflicted individual.