I'm not very good with sound, or discerning good sound from bad sound - so keep that in mind with my opinion.
But, from what I can discern, the quality is decent, the sounds are ok, but I would never spend the money on your sound packs on that site. You really only have a handful of sound effects, often repeated with slight modifications. Modifications I could make myself to a base sample, even with very limited sound skills.
I've bought sound packs before. I think I paid 50-60 bucks or something, but there were tons of different types of sounds, not just slightly altered versions of 1 or two sounds. There was everything from engine-like sounds to explosions, gunshots, more arcade-gamey-sounds, space lasers, etc etc. Nothing you've got in your samples isn't something that's not already in a dozen sound packs.
Most of the time I've needed sounds, they were fairly specific and I needed to combine and alter multiple samples to get what I needed. For example, the last sound I needed was a robot footstep. I needed to alter and combine a servo, a dirt-hit, a metal-scrape, and a thud to get what I wanted. The one before that I need a "railgun" sound. I needed to combine an electrical buzz with a muted gunshot, and a "charge up" sound. The charge-up sound itself had to be custom made from a heavily altered electrical buzz, since i couldn't find an appropriate sample anywhere.
Personally, what I think would be more useful is a library of cleaned up random sound samples for use in making custom sounds. What I've used most of the time is FreeSoundProject files. Unfortunately, copyright issues and quality issues are a problem with their samples. Pre-made sounds really only work for the most generic of games or for prototypes.
