xp pen g430 or g630:
Budget tablet, okay material used in making parts, nearly no lag, more accessiable
wacom 470 471 472 or 480
More expensive tablet, better, more smooth material used in making parts, nearly no lag. If you got these Wacom tablets, do your best to not break them since they are expensive.
Extra: you can good 471 and 472 new or almost new on eBay for around $70
Comment:
I own both xp pen g630 and 471. In terms of lag, they both are basicly unfeelable(which is nearly 0 if you dont mess up something). G630 is best for it's price, if you have the extra money, you can think about 471 (or other Wacom tablet) since for me, the material that made 471 has a really smooth, good feeling on my hand. Otherwise, g430 or g630 is good. (main difference between g430 and g630 is that g630 has bigger area).