I purchased this (351v) handheld as a birthday gift (Wood Look), I read a lot of reviews about the unit before I purchased this. I also purchased two additional brand named SD micro cards (FULLY Recommended, in order to install a newer better OS & Games, with the better quality sd cards). I did have an issue with one of the provided SD cards that game with the RG 351v (as they're unbranded and fairly rubbish), but! however this was quickly reified by DroiX and a replacement was sent out, which worked fine. So, I made a backup of the OS & Games provided straight away (getting free games was a bonus). However! with my new good SD cards I purchased myself, I downloaded the "351Elec" OS and used the games provided from the other SD card. After that! It was like a whole new quality system, the RG351v has excellent build quality, the controls are excellent, the sound is also excellent from the 1x mono speaker. It's one of the best "Retro" handhelds, I have every tried (and I've tested about 7 others) and this is the best... the screen quality is top notch, the buttons, joystick and d-pad are excellent (the feel as good, as top company controllers - XBOX, NDS, MegaDrive controllers etc.). I like the unit so much, I'm purchasing one for myself and I've also bought 2x SD Cards (32gb for the OS and 128GB for the Games - SANDISK), so I have the same setup, when my own arrives with the "351Elec" OS installed. I'll keep the provided OS & Games cards, as a backup. I 100% recommend this unit to anyone who loves RETRO gaming, its excellent for MegaDrive, SNES, MAME Arcade, Atari, NeoGeo Games, Dreamcast, PS1 and N64. With Dreamcast/PS1/N64, they didn't run great on the provided OS. However! that was just the OLD OS, but! with 351Elec OS installed and one/two minor scaling option changes (really simple to do, there is 2min YouTube Videos on this) it runs perfectly, like a dream.. Most importantly is, that this unit won't cost you a fortune and is easy to hold in your hand (ideal for travel on the train, plane or in your hotel from on holidays).