It's time

Two things come to mind, the first being battery life. Depending on the state of your A700 batteries odds are the A7ii will drain its batteries faster. More batteries / a grip might be beneficial, depending on usage scenarios.

The second is AF. If the A-mount lenses you wish to employ are screw drive then you need the LA-EA4. I'm not a fan of it, mostly due to a perceived shutter lag. If the A-mount lenses are SAM/SSM/HSM etc, i.e have their own focusing motor, then the LA-EA3 will let the A7ii focus the lenses. There might be a performance drop from what you are used to, I don't have the experience to say.

QuietOC wrote: If you want to use the same depth-of-field and shutter speed as the RX100 the A7II will show more noise. The A7RII has a much more competitive sensor as far noise and better AF performance. There is the Monster modified LA-EA4 if you want to use on-sensor phase-detect with screw-driven A-mount lenses. I haven't used it on the A7II, but it worked alright on the A7RII. I decided it worth it to upgrade to a used A7RIV, and I recently got the LA-EA5 for it.

Good point about the A7RII. It's not significantly more expensive if you shop around. I suspect that's going to be a much better choice, thanks for the suggestion.

The RX100 is a pocket cam for when I'm on the bike. It got me out of jail one time when a lens failed while I was traveling but its not used in any serious capacity. I'm mot shooting sport any more and not a wildlife shooter so the screw drive thing with the adapter is not going to be an issue short term either. It's just to help transition to the new lenses which is a fair investment. Current lenses are a mix of screw drive and SSM in full frame. I'm presuming the APS-C lenses are not going to be worth using on a FF body.

Batteries, I have a fleet of them for the A700. A grip is an extra thing to deal with, and having them for the A700, I don't see a need for casual shooting. I'll buy whatever batteries I need for the new cam in any case.

Currently Sony FE 12-24mm f/4 G, FE 24-105mm F4 G OSS, FE 70-300mm F4.5-5.6 G OSS look to be most suitable for a cut down travel kit to provide the same coverage I have today on APS-C.

But that's a down the track kind of thing and a whole other conversation.

I did not find the A7rII that problematic re. batteries. But YMMV. One advise: use a button to switch from EVF to screen. With auto, when you remove the camera from your eye, the screen goes on and keeps draining the battery, with a manual button, the EVF just turns off. Makes a real difference. Just put an extra battery in your pocket and you're set in my experience.

Seeing your use case, the A7r2 makes more sense then the A7II imho. The sensor is wonderful and the AF nice enough - especially when you come from an older camera like the A700.

None of the above. There is a reason Sony switched to the "Z" battery; the 50 was inadequate to the job. Yes YMMV, but if you're coming from the a700, you'll think the battery or charger has something wrong with it. Yes you can take a spare, yes you will need it.
But if you use a grip on an a700 and still need a fleet of batteries for it, I just don't see how you'll manage with an NP-FW50. Maybe an extension cord?
That said, and for the stated use scenario, the wise choice for the budget conscious would be the A7II since it's still available NEW with warranty and kit lens.
That said, you have to be printing really, really large at base ISO for the difference between the a700 and A7II to be seen.
If you're looking for a substantial bump in ISO for those casual snaps and considering the "pre-owned", I would suggest the A7SII. Most "S" shooters are into video and the shutters usually have low actuations.   

Edited by LAbernethy - 01 August 2021 at 04:54