searching for a bench grinder to give as a gift, but i know nothing about them...found 2 possible choices:
Delta GR450 8" VS Grinder with Tool-less Quick Change: Motor • 3 amp, Wheels • 36G & 60G, Diameter • 8" x 1" Thick, Face Diameter • 1", Hole Diameter • 5/8", Arbor Diameter• 5/8", Shaft Diameter • 5/8", Weight • 48 lbs., Wheel Diameter • 8", 60 Hz., 1725-3450 RPM, single phase motor, patent pending quick change/tool-less wheel changing system, flexible lamp, cast iron tool rest, eye shields, spark deflectors, coarse, friable, buffing wheels, adjustment wrench and diamond wheel dresser and instruction manual.

DeWalt 8 BENCH GRINDER 4.2 A/AC 3/4 H 3600 RPM 5/8 SPINDLE #DW758, 3/4 HP induction motor provides superior power for industrial grinding applications, Rugged cast iron base and motor housing provide durability and prolonged life, Motor runs at 3,600 rpm for high speed material removal, Precision-machined aluminum tool rests allow the user to accurately position work, Rear exhaust ports in wheel guards for a smoother operation, 12-1/2" distance between wheels for larger and longer grinding applications, Tool Weight 39.5 lbs, Includes: 36 grit wheel, 60 grit wheel, eye shields, spark deflectors, tool rests, adjusting wrench

which one is best or do you have a better recommendation?

Use?

Bur-King and Baldor are first rate Jet is also good. Deltas are disposable. I have no experience with dewalt.

I'd buy used... even as a gift, an oldschool one will be way more hardcore.  We have two grinders so we don't have to change the disks.  They're both mounted to the same stand.  I've never heard of someone wearing one out... assuming it's not being used professionally, but rather to sharpen the occasional axe or lawn mower blade.

We have a Sears one that was cheap, and an oldschool one that kicks ass.  Power isn't the most important feature, as it'll just spool back up as you move the blade to another position.  A shield is very nice, as it'll keep your eyes intact.  Lights are often broken and a gimmick, our Sears one has two lights... useless.  I think the tool rests get in the way, but I think the vast majority of people use a rest.

It's all about the stand!   Ours was built by my Grandfather.  He welded a pipe to a round base and melted about 40lbs of lead into the bottom... ROCK solid.  The base either has to be wide as hell, or heavy as hell... I prefer heavy as hell.