ive been hit-or-miss on the VXL systems. some have lasted a long time, others did not. Fortunately, traxxas did replace 3 ESC's over the years.
I will say, I have had a slash (rustler, pede, bandit ect) and it is not as good as a stock SC10rs. sure, with rpm upgrades and some metal drive shafts it is a tank, but in stock form not as tough as the sc10 IMO. and the sc10 handles better.
I have 25 lipo packs threw my sc10rs (figure that is about 12 hours total) and except for the rear tires wearing out (the rs version has softer rear tires than the brushed version) I haven't had to fix a single thing! and I have driven it as hard as any kid would.
My sc10rs was $310 with a 2s 5000mah lipo threw tower hobbies (I have tower saver membership, so shipping was free) Not at all bad for a tough, good handling, brushless RTR. I could have gotten it for under $300, but the coupon was $40 if you spend over $300 and the lipo was $35 or $40...so I basically got it for free.
what are the trucks that you use the 3s and 4s lipos in?