Which machine for DVR server?

I am running the DVR currently on Synology NAS 218+ unit with a Celeron J3355. 6g ram - storage to the internal array. I want to have best quality remote transcode performance as my family wants to watch remotely. I have plenty of upload bandwidth, but wonder if I should put the server on one of two other machine I have available (all do Quicksync, as far as CPU specs show)

Choices: DS-218+ NAS as above, Intel Celeron J3355, 6GIGs ram, 2-5400 hds in RAID config

Windows 10 PC, Intel i7-4500U mini unit, 8 gigs ram, internal SSD storage

Windows 10 PC, i7-2600, 16 gigs ram, internal HD storage, also has Nvidia 750ti (older graphics card)

Maybe little transcode difference across each platform? The Synology solution is simple, and seems to work fairly well now, need to test more remotely. The NAS runs a few other things, as does the i7-2600, though the i7-4500u could be a dedicated machine for this purpose

Also - final question - is it relatively simple to move existing recordings and database over should I decide to move from the NAS to one of the Windows machines? Thanks.

I would leave it where it is.

Moving is easy if you decide to do so. You can also setup a test DVR on the Windows machines and turn off Bonjour but enable Remote Access (after turning off Remote Access on the Synology) to run some tests.

If you do decide to move, simply move all DVR folders over and then reinstall and pick the "Restore Wizard" option.