The Slingbox Pro isn't supported on SlingPlayer for iPhone (and does not work at all on SlingPlayer for iPad). It's why you don't have the option to use more than standard quality ("SQ") streaming and why you only see one "dot" indicating a low stream quality.
That said it's a little unclear whether your Slingbox is on your internal network (a.k.a. LAN, your side of the router) or located offsite (a.k.a. WAN, out on the Internet), but I can share my experience with an offsite Slingbox AV (with 3mbit upload) + iPhone 5s + SlingPlayer for Mac OS X 1.0.10:
- iPhone 5s + Slingbox AV = 486Kbps stream (and it's incredibly rock solid around that number, as if SlingPlayer for iPhone is internally limited to that amount of bandwidth)
- SlingPlayer for Mac OS X + Slingbox AV = ~1100Kbps stream
I imagine that when SlingPlayer for iPhone negotiates a stream with the Slingbox it chooses a low resolution/streaming speed that is "appropriate" for both the lower bandwidth of a mobile connection and the hardware capabilities of the Slingbox itself. And while in 2013 mobile bandwidth is plentiful and hardware is powerful, the Slingbox Pro is built with 2006 techology and expectations. Your best bet is likely to get a newer Slingbox if you're heavily concerned about the stream quality.
Thanks for the reply. I did see where streaming hq to the iPhone from the Slingbox Pro is not supported shortly before your reply. I was referring to the pro being on the LAN not wan. I can stream sq at 500 Kbps rock solid to my phone. What I was trying to do is airplay from slingplayer on my iPhone to one of my several XBMC setups around the house, but unless it's a hq stream it will not AirPlay the video. It will only airplay audio. Only way to do sq is via airplay mirroring, but that is not supported on XBMC currently. XBMC will stream from the slingbox via a web browser but my setups are raspberry pi's or Atom ION setups. As you can imagine they can't handle flash video. Looks like my best bet is getting a 350 and taking two of my rental cable boxes back to my local provider. At $7 a piece a month the 350 will pay for itself before long!