which one of these amp to buy?

You haven't told us what your speakers are so we can't decide if you really need 300 wpc that the Emotiva delivers or not.

Somehow I'm guessing you don't need this much. And if I am right, then get the Parasound A23. It's the only one that is Class A/AB while the others are Class AB and will be the best for music. You will also get Parasound's outstanding customer service and will have the best resale value of the three should you ever decide to upgrade.

Agree on the A23

All are very good amps with Emotiva being probably the best "value". Emotiva have a very nice Class A, A/B monoblock amplifier in the XPA-1L. It produces 250 watts/ch. into 8 ohms (500 watts/ch. into 4 ohms) in Class B mode and 35 watts/ch. in Class A mode. It offers automatic switching from Class A to Class B.

All Emotiva amps come with a 30 day in-home trial and a 5 year transferable warranty. This would allow you to purchase the XPA-1L and listen to it in your system, always a plus.

http://shop.emotiva.com/collections/amplifiers/products/xpa-1l

-RW-

Another vote for Parasound. Have no experience with Emotiva, but I doubt it's up to the sound quality and reliability I've experienced with Parasound. Cheers.