To some of you this may be a silly question but, here goes! I have a desktop PC which has a built-in card reader. I only use the CF and SD slots. Would it be quicker to use a plug-in card reader or stay as I am? The other concern I have is that frequent withdrawals and insertions will cause wear on the card contacts.
A USB 3.0 card reader will improve downloading times into your computer, if your machine has a USB 3.0 port. I use 8, 16 and 32GB CF cards and they fly. I have never had any problems with contacts wear on Lexar and SanDisk cards. Just remember to eject the cards electronically before removing them. After a decade of doing it right I failed to do the above and ruined one card.
If you are running Windows, you can copy a large file volume from the card to your PC and read the transfer rate. I use a plug-in Lexar card reader and find the transfer rate to be as good or better than any of my USB flash drives. Of course, it's far faster than connecting directly to the camera.
Dan, I don't think the card reader will treat the Lexar or Sandisk differently.
If you want to do a little test, copy the files from the card reader directly to a directory you make on your hard disk and see if it's faster than Lightroom.
Even though I use 32GB disks and import to Lightroom on my 3 year old Macbook Pro, I seldom import more than 200 or 300 files at a time so I can't comment on the speed. But it is a little slow using the USB 2.0 reader. I am planning on replacing my main computer which is an 8 year old Mac Pro with G5 processor. That computer is really slow but I'm mostly changing to get the newest Adobe and Nikon programs which the G5 doesn't support.
Don't know what computer you're using but I had a similar occurrence with my last HP PC. The built-in card reader was MUCH slower to load photo files than using a dedicated card reader. That's all I use today. I'm not savvy enough to know all the tech specs of the two devices, but the time difference was obvious. See if you can borrow one to test. Failing that buy one from a good dealer with a favorable return policy in case that doesn't fix your problem.