The NUX MG-30 is top-notch for rock. For death metal, I connect the Amptweaker Tight Metal Pro II pedal.

For the money it costs (285), it is amazing.
It competes with much more expensive multi-effects. It has a sturdy construction (metal) and its screen is very good. It has a large number of amplifiers and pedals, I think enough for most. I was between this and the BOSS GT-1 and chose the NUX after a lot of searching...

Very good machine. Careful packaging, sturdy construction, with a large, colorful and readable screen. It has a very lightweight 2A transformer, and most importantly, an extra footswitch with 2 buttons that you can program to open/close a plethora of options, e.g. one for modulation and another for delay. If you add the control button that you can use as a tap, you have 3 real-time parameters in which you can intervene in the already preset sounds you have created. Sound customization is very easy, just check a couple of videos online because the manual is pretty useless. The sound quality can be excellent if you spend some time on it, as most of the presets are pretty awful, and we're always talking about the desired result, which is to play with this gadget plugged into a console or PA system, without carrying an amplifier. Okay, it doesn't give you the same feeling as a Fractal or Kemper, but for one-fifth of the price of a Kemper, it's perfect for the working musician who wants to get the job done quickly and easily. It fits everywhere, weighs nothing, and is generally recommended for studio (I haven't recorded with it, but I imagine it would be ideal), rehearsals, and live performances!

EDIT after 3 months of use, one pro and one con: The pedal is not suitable for use as a wah, especially in live conditions. It doesn't have a good feel, personally when I try to work it, the whole unit moves and I'm afraid I'll break it, so if you have space for a mini wah in your bag, it's better to take that with you.

The big pro of this device is that I recorded a demo with it and it went well, and now I'm recording an album again with it and it's going AMAZINGLY. If you really get into it and constantly improve your sounds, you can write whatever you want, plug it into your audio interface with quality that no one will realize you're not playing with an amplifier. Only the delays need a little convincing to bring out something extra, to be heard in the mix, with more mix on the pedal than you would do if you had the real hardware, but even so, the job gets done!