I've had the Amplifi for about 3 weeks now. I agree with a lot of the pros & cons that have already been voiced here. ***Footboard Issue solved, see edit below*** I'd like to add that I think Line-6 should have an accessory footboard specifically for the Amplifi. For example, why can you switch between the 99 presets on the Amplifi FX100 but that's not available on the Amplifi 150, then if you want a footboard you need to spend an extra $200 for the FBV MkII and you're still limited to the 4 onboard presets? I don't want to spend $200 on a footboard and be thinking, "well that's a bummer." Of course you can change the preset with remote app but that's a bit of hassle in my opinion if you want to be able to switch quickly. It almost seems like if you're going to spend $200 for the FBV MkII why not go for an extra $100 and get the FX100? Of course now you're spending $800 for both and it seems really redundant just to be able to have decent switching options.
Another poster also mentioned the issue with using a looper. If you're going to be doing basic looping then fine but with all the effects after the looper and no way around that you are limited. Line-6 has the JM4 looper which seems like a good solution as it has built-in effects so that's a cheap option I guess, you can then output all your loops once done separately through the stereo out and run an adapter to plug into the aux in (I haven't done this yet it's just an idea I thought of) and then you can play guitar and solo over that by running the guitar through the normal input. Or you can just buy some effects boxes or one of the Line-6 stompbox modelers and put that before the looper.
Now for the good. The remote app works great, looks great and is really easy to use. I use an iPhone 4S and the screen isn't too small, it's very well done. The only complaint is that if you go out of the app to access something else on your phone when you go back to the app it takes a couple seconds to resync. The tone match is a cool feature and I think being able to share your tones with others online and have access to their tones is brilliant. It's a lot of fun to see what others have done and then see if you can come up with something that sounds like an even closer match (of course this is highly dependent on the guitar everyone is using, for example the tone someone created might sound great on a Les Paul but not so much if you have a Strat so you can select a different one or create your own and publish it, amazing idea and it keeps things fresh). The 100 presets Line-6 has provided are all well done and super easy to tweak to your liking with the remote app. The fact it's a bluetooth player too is a HUGE plus, I use that feature all the time.
So here's what it comes down to folks, the price. For $450 - $500 you simply can't beat that. If I want a more professional set up I'd have to spend $1500 on a DT-25 & HD500X bundle or something similar. Now is the sound of the Amplifi acceptable for $1500, I'd say no but for $500 it's amazing. For me the only thing :"wrong" with it is the footboard issue. $200 and I can only switch between 4 presets? Um...or an extra $100 and now I have an Amplifi 150 and an FX100? I guess that solves the looper issue though and let's face it, if you're using a looper in such an advanced way that's going to require you to invest some $$$ on gear one way or the other. I also wouldn't mind some more inputs on the back, like how about a dual stereo input so I don't have fiddle around with adapters and whatnot.
I'm thinking of returning it before the 30 day window has expired but if I do I'm going to get a DT-25 & HD500X so it's not like I can return it and get something "better" in the $500 dollar price range, I need to triple my investment to get better so by that standard I'd say the Amplifi 150 is a great value and worth price. Line-6, the only thing is those of us that bought the 150 need a footboard that can access more than 4 presets, especially considering the FX100 owners can do this effortlessly.
So yeah, long story short is for $500 it's a great deal, you want better then you need to be prepared to spend 1K+. And if I do return it then now I'm out the bluetooth player and I do like the remote app. It almost seems silly not to keep it and just get the DT-25 & HD500X also.
**EDIT** - Someone told me in another thread that you can use the Shortboard to cycle between the 100 presets and those presets are in fact stored on the amp and accessible using the Shortboard without the remote app so that's really a huge improvement that I'm happy with. Also, I've decided to keep the Amplifi 150. For $500 you can't beat it as a practice amp & Bluetooth player and now that the footboard has good functionality, I'd say the Amplifi is a great bargain. If you want a more professional setup then prepare to spend $1500+.