I'm "meh" on Salomaki overall right now...
The first few games he impressed with his calm while still clearly putting up the hits with some much needed physical play on that 2nd line. The apparent calm/poise was impressive cuz so often we see prospects get into the mode of looking as though a guy is in an panic to "prove he belongs". Those first games in particular, Salomaki was getting in the physical game, all zones, while also being part of the offensive play, supporting puck movement, getting himself open, etc...
The last games though, it seems he's reverted to a more scattered solo aimless rush. He's still putting in the physical play, is near always hard on the backcheck and where he ought to be in his own zone, etc. But when the puck is moving back into the ozone he appears to be trying to figure out where to go and how to contribute. As in trying too hard rather than playing hard with a feel for his linemates.
I dunno if it's the prospect thing of getting anxious (with guys on the cusp of returning to the lineup) to prove he should stick, so like an issue common to call-ups on a leash, or if it's the 3rd line LW thing, so like an issue common to everyone who aspires to contribute offensively but is slotted into play with a center who is neither a power/physical space-making driver or a skilled/playmaking type.
All in, I'd think Salomaki is at least Bourque/Watson's defensive and physical equal, and from his first few games arguably a better fit into the middle 6 offensively. But whether or not he sticks over Sissons is a toss-up - as fans watching mostly only for 10-12 minutes of game time play, we really haven't seen enough of Sissons. At least I can't compare the two kids.