I went from a Losi EU to a Kyosho, and wouldn't go back. For me, the Kyosho is much easier to drive. With the EU I was forced to be really smooth, and drive carefully not to make mistakes, whereas with the Kyosho, I have the confidence to try and push.
The other big + as you mention is Tommy. Super helpful and knowledgeable
The Kysosho also seems super strong. I bought a second hand MP9 - not TKI2, and it is still in very good shape.
On the engine front, I did a little nitro in the 80s, and bought my son a TMaxx for Christmas when he was 3 (who was it for really

) so am not an expert, but the modern engines seem to hold a tune really well. I bought a second hand NovaRossi R21, which is a cheap engine anyway, and it has run flawlessly. Tommy is also Mr Engine Guru, and is always willing to help with tuning. He also offers a running in service, if you would prefer him to do it, which is free if you buy an engine from him.
I've found all the buggy guys to be very friendly, and happy to answer questions and to help. I was at Herts (in the snow) yesterday, and had no one to pit for me, but a couple of folks helped me out
For me, the biggest problem is that the smell and noise is addictive