well, actually TVT is very good choice, i know them since 2004th when they was tongwei video technology, not only TVT
i cooperated with them may be a bit less than 10yrs, and of course know a lot of pro and contra, but if say short- yes TVT is very good choice. few yrs ago they updates their VMS and i can tell it one of the best in China, quite nice design and functionality as well not bad stability, also 2yrs ago they launch so called n9000 generation products, and now their ip camera web UI and VMS as well NVRs/DVRs got those nice and common UI(local GUI and web UI as well VMS and mobile app).
some months ago they released new dvrs which much more competitive than in past, not only by features but finally by price as well. if say about nvrs, also very well products in all terms- features and price. ip camera- well, i can say its are competitive, not magic but fully competitive, and getting better, new features and UI brings its up, well price is less than major players but a bit higher than Raysharp for example or such low prices products you can find from Nihon or Longse. but as total partner- i think their offer is very good.
about ahd- honestly speaking, ahd in my point of view is mass...entry level, so, not sure their cameras will be strong offer, but!! dvrs- 100% best choice.
additionally ahd cameras no problem to find your choice- from lowest price to high quality.
i know that as spent already almost 20yrs for such research…
what else... they are really big factory, good QC system, RnD is strong even i always feel they are lazy(joke)
RMA- no question, works well, i can say they only 1 company who offers if you really need, so called service manual( a doc for repairment) they can issue it, most of(99%) never do that and even can`t.
if you wanna i can share a lot of images and videos of their factory.
and- I'm not their employer, really. just still like this company even 10yrs experience brings me a lot of negative as well… but even so- more positive. if you will meet Mike Guo or Joe Qiu say hello from me.