Criteria:

• Two channels for mic and guitar
• Input for tracks (phone, laptop, etc.)
• Good reviews
• $400 and under

Here's what I found...

1) Fender Acoustasonic 40 - 40-watt Acoustic Amp ($200)

We carried these years ago in my store. A lot of bang for the buck. 

2) Bugera AC60 60-watt 2-channel Portable Acoustic Amp ($293)

I’ve never heard of this brand. It looks like it’s proprietary to Sweetwater. The good news is Sweetwater has a reputation to uphold.

3) Fishman Loudbox Mini BT 60-watt 1x6.5" Acoustic Combo Amp ($350 - I’ve included the link for the bundle… good deal)

Fishman is one of the best brands for acoustic amplification. This looks like they'e smallest acoustic amp.

4) Fender Acoustic 100 Guitar Amplifier ($400)

Good reviews and looks beautiful!

5) Behringer Ultracoustic ACX1800 - 180-watt 2x8" Stereo Acoustic Combo ($400)

Behringer is known for a lots of features for a low price… not necessarily high quality. This amp does have a lot of features for the price.

Note: Reproducing the sound of a guitar, voice, AND background music is a lot to ask of any of these amps. They all have comparatively small speakers and low power compared to what I'm accustomed to in performing situations. 

This may not be an issue for you but you’ll want to keep your expectations realistic. 

That may depend on what you want to use it for. Practicing in a small room by yourself sitting close to the amp is much easier than playing for a room full of people.

You can call Sweetwater and tell them what you’re looking for. Ask their opinion as well. They’re usually very helpful (but are likely short staffed right now).

Footnote: Companies measure watts (loudness) using different criteria. Two amps that are rated at 60-watts don't necessarily have the same loudness.