Fl gunner,
2018 is a big year for RF's, so unless you are in a hurry, you might wait a few months to let things shake out a bit.
I have used Leica RF's for a while, currently run a 2700 with a Kestrel Elite. I did a review on the RF on another site, working on the second part that lightly covers the Kestrel but focuses more on the workflow. Putting ranging performance aside (the top ones are all pretty good in this regard), its the other functions that separate them at this point...IE the data they provide and how you can access it.
As there have been so many developments recently and more coming (Sig BRX series, Vectonix X, new Leicas coming), some points below will be based on expected performance, as the new stuff is untested.
But assuming your budget is about 1150 ish, and assuming you want to pair it to the Kestrel Elite or ballistic, here are some choices (there are others!) with pluses and minuses IMO:
Leica 2700 and Kestrel (Either Elite or the Ballistic).
Upsides: Both are available and tested now. Leica optics are tops. The custom curve option makes onboard ballistics trustworthy until you get to where coriolis and aero jump matter. Return from this limited to 1000 yards if using custom curve. Strong ranging performance in all kinds of conditions.
Downsides: May bust your budget a bit. RF itself, does not take into account advanced stuff like Coriolis etc., so at some point you are moving to another solver. Kestrel takes care of that, but data entry is manual.
Sig BRX Series and Kestrel
Upsides: Theoretically, best workflow around, as it dumps all the info right into the Kestrel, and as it was explained to me by Sig, the Kestrel can feed that back into the RF. So range, let the kestrel do it's thing, it feeds it back to the RF and you have everything, similar to the 2400 ABS, except all the work is done by the Kestrel instead of inside the RF (there are pluses and minuses to that vs the ABS).
Also has a stand alone ballistic solution...AB lite. Like the ballistics on the Leica, it does not take into account advanced forces on your shot, but is good for medium to medium long range (it is limited to 800 yards for this return)
Cost wise, you can pick up whatever model you can afford to make work with your system, from a 1400 IIRC, to the 2400. Pick your price point.
Downsides: Just released, so you are a beta tester to see how well the system really works in the field. Glass is not in Leica's league....which can matter depending on when, where, and how you use it...YMMV. Incidentally, there will be a BRX bino coming out shortly as well if you like that setup...IIRC, it's in the 1200 range.
Leica Vaporware and Kestrel
Leica is bringing a response to market that will work with the Kestrel. Exactly how, could not get further details. But my guess is it will probably work like the Vec X...range, it will dump it to the Kestrel, but will not feed back like the BRX is supposed to do. You will have to look at the Kestrel to get your shooting solution. But that is totally conjecture at this point.
Glass will be top notch. I would guess ranging will be in the 3000 to 3300 yard range, which it will probably achieve under difficult conditions, if past performance is any indicator.
Downsides? It is already late...don't know when it will actually come out. And the price is likely to be higher than the sig products. And again, you will be a beta tester. Leica has generally been good about it's products working on new release because they have been iterative...but this will represent something new in terms of connecting to a Kestrel, so there is risk there.
HTH!