The Neo-Geo X has some wildly varied opinions. I can't remember a system having as such. Most people here say it's trash. Some say it's mediocre, could've been executed better. Some say it's good. I bought mine with the Mega-Pack back in November or December 2013. I was excited about the unit, because I had gotten rid of all my authentic Neo-Geo stuff when I moved in early 2013. When I got home, and took everything out of the box, I felt the feel/build quality of the handheld was good, however I was disappointed with the lcd screen's picture quality as compared to my modded psp. Even more so when I plugged the unit into my 27 inch CRT TV with the composite option (terrible). The remedy to this was to purchase a hdmi to composite/s-video converter which greatly improved the picture quality on my CRT.
I later bought a couple 4.50 firmware sd-cards off ebay with the emulated systems/games, and I was happy I did. Playing via the handheld at my desk on my 18 inch lcd via hdmi going from ATARI 2600, GB, GBC, GBA, NES, SMS, SNES, GENESIS, CPS1, CPS2, NEO-GEO, PS1 is hella convenient. Not being able to save my games like on my modded psp is a slight bummer though. I have Android devices (JXD models, GPD, and Chinese and Russian handhelds) that can do this also. Overall, I like the NGX. I have 2 complete in box models (I saw one at a retro gaming store in like new condition for $129.99 a couple years ago and couldn't resist), and a total of 4 of the handhelds (handhelds came included with the two 4.50 firmware sd cards I purchased).
I agree, that the NGX is flawed, but it's not trash. I've played/have similar devices that have worse emulation, and picture quality. I've seen youtube videos with people who own a real AES, and purchased the NGX, and have stated that the quality of the controller, and emulation is not exact, but it's not waaay off like a lot of people have said. Everybody's got an opinion, everybody's going to feel how they feel when they spend time with it. If you enjoy your NGX, cool. If you didn't, cool. Do you.
I like the NGX, but I do feel it could've have been executed better. The emulation is not %100/1:1, the screen quality of the handheld could've been better (PSP better), and if I hadn't utilized the hdmi to composite/s-video converter, It would be painful playing the unit via the composite video out on a CRT (HDMI is acceptable for me). My NGX still get's ample play time, it's in the rotation of my many game systems, and handhelds. Again, your experience/feelings regarding it is just that, yours. To me it's not bad, not great,...decent.