SK,
From your post, there are three negative reasons you've identified against going to the US:
1) "I want to fly here." I agree with the idea of training where you plan to fly. But it sounds, from your post, as if you've done your PPL in the UK. And your hour-building. And you'll do your IR here. You have plenty of experience of UK airspace already. I would think that a bit of variety in seeing different ways of doing things would be a benefit, not a disadvantage.
2) Adjustment - not just to R/T, but to airspace and so on, too - once you get to the US. You've read my diary, so you know about the "pre-CPL" which EFT have you do before starting the course. Obviously it will take you a little longer than me, since I already had a reasonable amount of time logged in the US, but it's not very difficult and shouldn't take too long. The question is, will the time and/or cost of this negate the time and cost advantage of going to the US. I don't know the answer to this, but you can probably make some reasonable guesses about how long this will take, based on my diary, and work it if it negates the benefits or not.
3) Impact on your IR. I would say there will be zero impact on your IR. The CPL is a VFR course, and the procedures, R/T, etc are completely different to flying airways (I would imagine - having not done the IR myself yet). So I can't see how your choice of location for the CPL would have any effect on your IR at all.
There are plenty of other good reasons not to go to the US. Family connections or work connections in the UK are the obvious ones. Also, if you've done most or all of your flying so far abroad, then doing the CPL where you plan to actually fly is a good idea. But these don't apply to you.
Good luck!
FFF
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