I have been playing a Forest Gnome Arcane Trickster in a bi-weekly game since Tasha's came out. We are currently 4th level and here is a summary of my experiences:
With the new Steady Aim ability, I find it much easier to gain Advantage every turn with my Light Crossbow. Out of sheer stubbornness, I don't use an owl familiar. I use a weasel instead. It rides on my back and grants me Advantage whenever I use Booming Blade (it readies the Help action to trigger whenever I come within 5 feet of my target). I don't have Greenflame Blade, though I was planning to pick it up later. In practice, whenever I use Cunning Action Disengage with Booming Blade, I find my 25-foot movement rate fairly restrictive, particularly if I need to move through allies to get to where I want. As a result, I find myself relying on ranged attacks more than I would like. To resolve this problem, I am strongly thinking about picking up the Mobile feat at some point after capping my Dex.
All in all, I find that I am landing attacks much more reliably than just about everyone else on the team. I also love that I am able to contribute meaningfully to each and every pillar of the game. Although I have tried to play almost every other class, Rogue remains my favorite by a considerable margin. Every time I try to play something else, I find it somehow lacking! The changes in Tasha's have made the experience even more enjoyable for me since I no longer need to contrive a way to Hide every turn in order to gain Advantage.
Cheers!