Which way should I draw?

NSDrawing.swift

import Cocoa

class ViewA: NSView {
    override func drawRect(rect: NSRect) {
        let context = NSGraphicsContext.currentContext()?.CGContext

        CGContextSetRGBFillColor(context, 0, 0, 0, 1)
        CGContextFillRect(context, bounds)

        CGContextSetRGBFillColor(context, 1, 0, 0, 1)
        CGContextAddArc(context, 50, 50, 25, 0, CGFloat(M_PI * 2), 1)
        CGContextFillPath(context)
    }
}

class ViewB: NSView {
    override func drawRect(rect: NSRect) {
        NSColor.blackColor().setFill()
        NSBezierPath.fillRect(bounds)

        let box = NSRect(x: 25, y: 25, width: 50, height: 50)
        let circlePath = NSBezierPath()
        circlePath.appendBezierPathWithOvalInRect(box)
        NSColor.redColor().setFill()
        circlePath.fill()
    }
}

let frame = NSMakeRect(0, 0, 100, 100)

ViewA(frame: frame)
ViewB(frame: frame)