That's probably because after playing for years a large amount of people settle with TM as from their experience they're the best option. People who bias towards what they own are simply kidding themselves, some of my own posts comment on how crap some of the stuff I buy or have bought is, I'd have no motive or reason to favour TM if it didn't perform as desired- you'll probably notice I have significantly more WE stuff than TM which again we all know are hit and miss at best and I'd happily say so and actively often recommend against buying.
Spares and mags won't be easy to find, pretty sure they're out of production. TM are the standard spec so easy to sort, they shoot well and are reliable, get a TM otherwise you'll just end up regretting it.
Not saying they're bad just that being used by a military isn't enough to suggest they're great. Uktactical tend to sell decent stuff though so I'd be surprised if it's not decent.
All manufacturers have bad ones and lemons, probably nothing more than that. We all know how good g&g stuff tends to be and most people appear to rate the firehawks in particular very highly so doesn't look to be the norm
It sucks but I imagine they view most hpa users to be relatively well versed in airsoft tech stuff etc so stuck a crap one in to lower costs with the expectation of people changing it.
I'd go M&P (I did infact ). Runs very smooth and reliably and shoots great. It might be possible to swap the mag release to the other side too- the mags have indents to suggest you can like the real one. Slide release and safety are both ambi-friendly so good all round really.