Well, besides the obvious difference in stocks, I think that the only other major difference is that the Tac comes with both a power and hammer spring adjuster wheel, whereas the Classic only comes with the power wheel. For someone only recently into air guns, perhaps the simplicity of the Classic is a better rifle to start with.
My wife enjoys shooting a Classic in .22, and I like how that rifle handles and shoots as well. The combination of the power adjustment wheel, the externally adjustable regulator and the ability to easily and inexpensively add 1 or 2 FX Power Plenums to the gun has given us all the adjustability we have required to shoot pellets at the velocity we want, for the accuracy, power and shot count we prefer. Plus she grew up with a grandfather who was an avid hunter, and she has more of an appreciation for traditional, wood stocked rifles than she does for AR type styling.
If you are going to use this rifle for hunting, don't know what caliber you are looking to get. But we also have a similar rifle to the Classic (a Dream-Pup), and it is in .25 cal. When I added 2 Power Plenums to it and left the regulator alone, it was shooting FX 25.4 gr pellets at an average of 945 fps, so the Dreamlines can definitely make some power. I ultimately turned the regulator down by about 35 bar and we are getting the power we want at a muzzle velocity of 880 fps, and a good deal more shots per fill. Plus a smoother shooting rifle.
Good luck on you choice - they are both very good rifles with more similarities than differences.