Bought a new McIntosh amp

You have purchase a very significant and important piece of equipment. Enjoy it, let it break in. Get to know it. Many people lust after such a piece of hardware and could never afford it. It is a piece you could easily keep for twenty or thirty years and be proud of owning. Given what you have said about your equipment, this is the highest performance piece. So, if it doesn’t blow you away, then over time as you upgrade other pieces you will realize it’s potential. 
Great decision. Enjoy.

Your overthinking my friend, information saturation can make you crazy. My advice is to enjoy what you purchased and stop doubting yourself. Mcintosh makes exceptional equipment. After a while and a proven assessment you should expand your mind and try something else. BTW maybe even find some time to enjoy the music.

I did exactly what you're about to do....! I bought the MC152 brand new with a pair of Sonus Faber Sonetto 8's... Brought them home.... Unpacked and set it all up and it sounded lovely...! Then, I went to another dealer nearby my home and he A/B'd that 152 with a bunch of other amps and that's when buyers remorse set in. I wound up selling the MAC and buying a Gryphon Diablo 120 instead. That's an integrated amp. Ooodles of gorgeous dark - clean - precise - tight soundstage....!

Now... All that said, I've since rotated my system this past year and continue that elusive path to sonic nirvana. 

Go with your gut...! I LOVE the way Mcintosh gear looks...and I've owned a lot of their fab products.....but there is so much great gear out there.... 

I sold the Diablo 120 and bought the Diablo 300
I sold the Diablo 300 and bought an ARC 160s
I'm about to buy the ARC Ref 6SE

I landed on a pair of Sonus Faber Serifino's that I love with ALL the amps I've had...

If your'e at all like me...this is just the beginning...!

Good Luck...!

Give it some break-in time, the sound will just get better and better as you use it. It may sound “ok” right now but once it’s broken in, you will say “wow” Also using good quality cables helps too.

I think most people agree that if you have doubts and as you are on a budget, then take it back as it could end up being an expensive mistake. I tend to agree you would get more benefits out of a speaker change. However if you go for the Klipsch I do not understand why people are suggesting so much power for a speaker that is 99db. A 16watt tube amp at a theoretical full volume would give you 111db. A friend of mine is driving 96db speakers with an 8watt 300b amp in a room that is 22ft by 13ft and that goes as loud as most sane people would want, and like playing my music loud!