James - Not sure if you saw my most recent posts, but the current setup is as good as I can make it given my circumstances. However, circumstances soon to change and the first thing I am doing is getting the room properly treated, ticking this off the list!
In all honesty, I don’t have a massive interest in playing around with preamps. What attracts me to the Apollo range is that I’m able to affordably have flexibility in choosing what works best for my needs... it’s a pretty scary thought dropping potentially thousands on a preamp that may not make a huge difference, and may not even be the right fit if it does make a difference! The flexibility and affordability of UA is what has therefore appealed to me (as despite the unit costing a lot up front, the later costs for various plugs is reasonable).
However, what I’m now feeling is along the lines of CS70 - I think I will get the UA, but not now. Firstly, I’ll spend my money on getting the room as good as it can be (I have some daily ambitious plans for my new studio in general, so that’ll take some time to get right). And then perhaps a new microphone as an addition to the 414. And instead of buying a £1.5k new machine as the temporary solution, maybe a £200-300 temporary AI until I have the necessity to buy a new machine, which will no doubt happen someday. And then I’ll see what the world of USB/Thunderbolt/AIs is up to...!