Hi Chad, welcome! Nice to see some real bicycle guys here!
Building a 4-stroke definitely costs more up front, but in the long-term, I feel it proves cheaper - especially if you intend to use it for daily transportation.
The 4-stroke is simply smoother, more reliable (most are industrial-rated engines), and you don't need to mix oil in the fuel. Most use less oil than 2-strokes.
$200 can easily buy you a chinese Honda clone motor. You need everything else tho lol
The china 2-stroke is more compact, cheaper initially, makes more power per cc, but it's like playing the chinese lottery when you get one. To start with, they are generally not balanced well and have "dirty" castings. Second, they usually have mediocre bearings. Third, the cylinder jug is the biggest glaring weakness of them. No matter what mods you do, you still have that 1930's era Russian-designed cylinder. The chinese 2-stroke is not designed for sustained operation. Older instructions say to shut them off every half hour and let cool.
Don't get me wrong, I'm not hating on the chinagirl. There are many here who are successful with them. I spent 4 years riding bikes powered by them. If you like to tinker and tinker often, they fit the bill. I'll probably get another one for a really fun toy bike or something. I will never use one for a dependable daily rider again, however. 1 year with a 4-stroke Huasheng is enough to change my mind.
No matter which way you go, you must eventually get a chinese 2-stroke for the experience tho!