My RT-X 27
well, i am new to threads, so be patient with me. the rt-x 27 was my first nitro vehicle. i have always dealt in electric & brushless until now. i bought mine from tower, when it was $100 off. my overall experience has been positive, but has not been without headache. i rate this truck a 7 out of 10 as far as RTR's go. here are the things i have seen and/or recommend:
1.) i smoked both servos when i used a NiMH 5 cell RX pack

. i am not sure why this happened, unless the stock servos were not rated to support the initial 7+ volts seen with a fully charged 5 cell pack (1.2 volts/cell nominal, ~1.4 volts/cell fully charged). for cost purposes, i replaced the steering servo with a Hobbico/Tower Hobbies 170 digital servo, and the throttle servo with a Hobbico/Tower Hobbies 140 digital servo. no issues to date with either servo! also, i tightened the servo saver on the steering servo, as the added 333 oz-in of steering caused the saver to work without turning my wheels.
2.) i use a futaba 3pm 2.4 ghz radio system, so when i replaced the servos, i replaced the rx too. works great and the 3pm 2.4 ghz, when used with NiMH rx packs and digital servos, has a built in programmable Fail Safe

to help prevent run away nitros. other radio systems may also have this feature, but it's nice not having to buy a Fail Safe module. also able to adjust end limits on servos to reduce servo strain, a big plus+++.
3.) after break in, the truck ran great until i ran out of Duratrax 20% Red Alert fuel. i bought a gallon of 20% O'Donnel fuel as recommended by Duratrax, and i think it was a bad gallon of fuel

. this fuel caused many issues, but lead to more discoveries. please note, i am not bashing O'Donnell fuel, as a bad gallon could happen to any fuel manufacturer.
4.) seal your nitro engine first! when troubleshooting my fuel issue, before i knew it was an issue, i did a lot of research. i will say, sealing your engine helps no matter what. even though my engine was not running well, the sealing gave it cooler running temps. check out this thread, it is a pretty good one. total cost for supplies to seal your engine, less than $10!
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5.) after swapping out the recommended Medium temp duratrax glow plug for an equivalent medium temp o'donnell plug, and finally finishing the gallon of O'donnell fuel, something amazing happened. my next gallon of fuel was 20% Traxxas fuel, i wanted Byron, which makes Mugen Seiki and Hobby Gold fuels too with no difference here in my home state of Iowa, but my LHS was all out, so Traxxas it was. the stock high speed needle settings of 4.5 turns out, with a running setting of ~4 turns for the O'donnell fuel, with the Traxxas fuel, ended up becoming something like 2.5 - 2.75 turns out. I know what you are thinking, but i did this with 1/12 increment turns and a temp gauge. the engine wouldn't even turn over at idle with the stock setting of 4.5 turns out because the fuel/air mix was so rich. at 2.5 - 2.75 turns out, i was shocked at how well the engine idled, and WOW, what a difference in performance. i had run the o'donnell plug with the o'donnell fuel, and had the same results, so i know now that i had a bad gallon of fuel, as the Traxxas fuel kept me engine temps low, increased my low end torque response, and made the truck run like it was supposed to.
finally, after all this, i busted a tie-rod end when my 3 year old ran it into a stake in the ground

. the replacement part is on back order from tower hobbies, and i discover that the rt-x 27 is discontinued

. for $200, i recommend this truck, but please note my modifications above.
i hope this helps someone out. in case you are wondering, this truck has several brothers: 2 Traxxas VXL Rustler's, 1 Traxxas Emaxx w/Novak HV 4.5 system, 1 Duratrax Evader EXT, & 1 Kyosho Turbo Ultima II from 15 years ago

!!!