We have a big collection of smokers, including an MES and several pellet smokers. Can't beat pellets for convenience, but the MES can be quite good if you mod it a bit.
An MES from the factory doesn't really have a good mechanism to make smoke. Their pitiful little burn tray just doesn't produce much flavor.
I like Todd's amazn smoker tray/tube for the MES. Big improvement. Todd gave us several to sample a few years ago and they work well. He actually designed his smoke maze specifically for the MES (fits perfectly).
I tried something different recently you might want to consider before you drop your MES for a pellet smoker. I picked up
Masterbuilt's cold smoke attachment (about $50 from
amazon) for my son in law's MES while we were visiting so he could smoke a brisket for new years. The cold smoke rig is really just a smoke generator. The MES generator is really easy to assemble/install (took about 5 minutes). You load it up with chips and it puts out a LOT of smoke. It put out about 4 hours on a fill of chips (couple of cups?) before we had to refill it. Nice smoke. Brisket came out great. Nice thing about the cold smoker is that you can use your MES to cold smoke cheese, salt, etc. because the burn heat stays outside the unit.
One other advantage of the MES rig is temperature independence. In a pellet smoker. heat and smoke come from the same burn pot, but they are inversely related - the hotter you go, the less smoke you get. This makes pellet burners great for low and slow smoking, but not so good if you want to cook hotter. With the MES and cold smoker/smoke generator, smoke output is constant, so you can set the temp as you please.
So, leaving that aside to answer your first question: for inexpensive smokers, I am partial to Danson (danson.com) - they make pit boss, louisiana grills (country smoker, LG), etc. Their short auger/end burn system (similar to the system on yoder's high end smokers) is much simpler and easier to manage than the long auger /center burn systems used by most companies (IMHO). I personally strongly dislike Traeger products. Huge marketing budget but weak products with weak support. I think one of the most innovative smoker makers is
camp chef. Their smoker has evolved at an incredible rate. Years ago (7?), their product was just OK, but it has become very good. It is a rapidly evolving market.
To answer your other question - IMHO, the "carcinogen" scare is wildly over-hyped. It comes up every few years. Quality cooking pellets are just hardwood that has been compressed. So if you are willing to eat food cooked on wood (sticks, charcoal, etc), food cooked with pellets will be no different.