Firstly, thanks for adding this class, it has quickly become my favourite in the game.  I really like the aesthetic (barring the odd cardinal hats) and I enjoy running around with a stompy robot army.  Praise for the voice acting too, it all really works well for me.  I currently have a tech adept at level 74, have run the campaign, warzones, ordo missions and void crusades and in the main have had a lot of fun.  The campaign was also good and the way of introducing the inquisitor to the main ship hub reasonably neat - though I did like the original tech ship captain and it is shame not to be able to use him more.  Lastly, I like the customisability of the character in terms of choosing and equipping constructs - it feels like I have more choice than some other classes.

Onto the not so good.

• the weapon selection is underwhelming.  only 8 equippable weapons available and no crossover with other classes.  I'm also not sure if the weapons themselves have enough unique features to distinguish them
• without heavily compromising the constructs, the tech adept does very little damage on his own as there is no crossover with passives
• The pathing for the constructs could do with some tweaking.  My Kastelans often get stuck on terrain and left behind, only catching up when I move far away
• construct target selection is an issue.  They'll often be off attacking something minor whilst a big bad is smashing us. It'd be nice for example if they targetted whatever I was shooting at so that it was possible to focus fire on things like toxicrenes which can make a mess of them.  speaking of which...
• constructs are a bit fragile, particularly the smaller ones.  I'm running two +50% life psalm doctrines, a full construct defence passive tree and some defensive items in the equipment modules but my vivisectors still melt quickly and can be pretty much one-shot by things like toxicrenes even on +0 difficulty.  Kastelans do mostly stand up pretty well to punishment but even they can be burst down if not careful.  They also heal slowly, even with assistance.  Characters can benefit from the innoculator or even being able to make themselves temporarily invulnerable with a rosarius or psyker shield.  Constructs just take the damage.
• construct damage is a bit low compared to other classes even with a full construct offence tree and two +50% damage psalm doctrines.  Since only the construct passives affect them it is not possible to beef them up with things like the crit tree or even get them adding their own debuffs to enemies.  At higher difficulties (+4 and up) I'm having to try debuffing enemies myself otherwise kills on champions etc can become really quite slow.  A lack of armour breaking or piercing abilities really hurts them too as armoured opponents take much longer to kill
• speed.  A combination of low personal damage, non optimal target selection from constructs and them getting stuck on terrain means that fast moving opponents like the wandering servo skull are a real issue.  It gets away from me.  
• Mission speed is also an issue.  On a mech enemy map, my constructs were taking a lot of damage, including my kastelans.  Even though it is possible to actively help heal them it still takes a while to recover 10-20,000 hit points so I spent a lot of my time sitting and waiting to repair.  If there had been a timer on the mission, it could have been a fail.  Any other class would be able to pop the innoculator and move on straight away.

I should be clear that for me the negatives are just things I think need tweaking.  In the main I think Prophecy has been a success and I've already sunk a lot of hours into it.