.40S&W is higher pressure, higher velocity round, which inevitably makes it snappier.
9mm is easier for a beginner, that is true. I have some experience, and I love shooting all three calibers mentioned here - 9mm, .40S&W, and .45ACP.
The HKs handle .40 quite well, but the full-size USP or P30L, due to their mass, tame the recoil better. P2000 is smaller, so relative to the bigger brothers, it flips more.
I have not done comparisons with all guns, but from what I have tried the HKs are amongst the top in handling .40S&W.
Walther P99 in .40S&W - that flips like crazy due to the excessively high bore axis.
The Glocks are not bad pistols. Except they have one fatal flaw - the disgusting trigger. <insert puking smiley here>
If you have a Glock you will have to change internals with aftermarket parts.
The Glocks are just overhyped and overpriced. Think that Glock is Honda.
I do not buy the story about the triggers. Shooting both striker and hammer-fired handguns helped me to learn to shoot better.
Later, when I got a revolver as well, it helped me learn more.
There is no reason to sell the P2000. It is an excellent gun.
If you want a decent striker-fired pistol in the same size as Glock 19, take a look at CZ P10-c.
if you really want 9mm in the P2000, EFK makes conversion barrels for P30 from .40 to 9mm, which will fit in P2000. Currently, they do not have them in stock though.
if you really want to sell the P2000 (which I personally recommend against), post it here.