I got the Vox Amplug 2 Metal quite some time ago and I believe I can be somewhat objective.
- quite small, fits in your pocket, very easy to carry;
- the rotating jack makes it even more portable and you don't have to worry about the jack getting twisted off the body;
- the 3 types of overdrive/distortion can be quite useful combined with the Gain control, you can get a lot of different sounds in terms of intensity and sharpness;
- the battery life is quite long. I honestly forget that it runs on batteries...
- the knobs for gain, tone & volume are turning smooth and a big enough to give you enough grip and control;
- these knobs are very responsive so you can really tweak the sound to your liking;
- the effects (reverb, delay & chorus) are not very useful, at least to me;
- the overall build quality feels a bit cheap and flimsy;
- would not recommend for playing with low tuning (e.g. C, Bb...), as it gets quite muddy;
- as the batteries start to drain, the sound gets dulled down, which you might not pick up on right away if you are playing for hours at a time;
- there is a small latency that is quite audible if you spend enough hours playing with it. It's not big but for more technical and precise parts, it will definitely throw you off. To "counter" that, I found that what works for me is turning the volume down a bit, moving the headphones slightly away from my ears and listening to the picking of the strings as a "time reference" while the distorted sound is still playing from the headphones.
- I have to point out that I do not have a "proper" guitar amp so take my findings with a grain of salt in terms of discussing the sound;
- in general, the sound it gives is a bit "fried", edgy and "grindy" even on lower gain. I assume it's to be expected, but it's worth pointing it out. Another way I can describe it is that even on lower gain and/or volume, it still sounds as if there's a gain knob somewhere turned to 11/10. It's very subjective of course and it also depends on the guitar and pickup position;
- this version doesn't have a "clean" sound, you can't completely turn off the overdrive;
Overall, I'd say it's a very good budget solution. For what it's expected of it, it does great. If you're a casual player or you're not sure if you want to get into playing more seriously, you won't regret getting the Amplug.