I was just frankly excited to see so much Deathwatch art in Primaris gear. That bodes well for the codex and means that the 'elite' force nature of Deathwatch will be preserved in the form of Primaris.
What I don't like about this is I bought just about one of everything for Deathwatch, including that incredible deal they had last 'Black Friday' with that terrible formation in it. I have no idea how to use this stuff going forward.
The middle ground reaction I have is that a lot of the Primaris stuff is VERY mediocre. Very limited in battlefield roles, very inflexible, and almsot always footbound, unable to use the great Corvus Blackstar.
I play Ultra a lot... I played them a lot this weekend at the Astramis phase one Konor campaign (personal games and the store), and in the past weeks I've used almost exclusively Primaris stuff. I hate to admit it but the vanilla marines do very, very well without these guys.
A Landraider is still a tremendous choice. Cheap dev squads still do very well. Scouts (for marines) are a very easy go to in those detachments for troop choices. The Razorback is flat out an easy choice to put an around around.
Deep strike your non-primaris Watchmaster in the middle of your flyers, and race up some razorbacks and you have a very solid shooty baseline to work a solid list from. Now add in Primaris and it gets confusing... frankly it's a bit awkward because you want to mix in different armour types but it's all exclusive. Space marines can't go in the Repulsor, yet Primaris space marines can't go in the Landraider. Very frustrating at times and it leads to an awkward playstyle.
The simple answer is... get our apothecary, and Helblasters and advance behind a Landraider/Razorback whatever... or wait on the Repulsor and load it up with your solo squad of Helblasters.
About the Redemptor dread... again I'm using this in my Ultra's but only for aesthetics and background (I actually very much like the model, and the background of it) but it's just a chaff killer and at conflict with using that tremendous (S14) arm, wanting to move, but penalizing your plethora of S5 shooting.
Primaris overall seriously lack high damage volume fire. The Helbalster is the only go to in that area and while a solid foundation, they are the best of the worst for going after the likes of landraiders, or solid, tough targets.
It's great to have access to the line up though, and hopefully it continues with the Redemptor, etc, but in actual playing terms, I'm not sure what you really do with all of this as I've found it to be 'fun' in my Ultra lists but every game I think... 'how am I going to make this work in my Deathwatch?' (an already expensive, low model count army with specialized weaponry suited to different jobs on the table).