Need Inputs on a Modestly Priced SS Preamp -

I need to upgrade my solid state line stage preamp. In looking at the market, I found there is a growing number of products that seem to offer very high performance and value priced from $500. to $600. They all have some good reviews. So, does anyone have experience with any of these products? Or can you suggest other products I should consider?

• Schiit Audio Freya S
• Singxer SA-1 (found on the Drop.com website)
• Gustard H16  (also found on the Drop.com website)
• Topping Pre90

I would prefer a unit with a balanced outputs and a headphone amp, but I am flexible on this. 

Thank you!