I would recommend you to have a look at https://www.qhoster.com/clients/cart.php?gid=15
It seems that for ~ $6 per month you will be able to have good VPS.
I would agree regarding libertyvps.net - they are good one. But they are offshore host, so you need to make sure you are looking for offshore based one.
Actually, VPS services are always different. It could be SSD, KVM, OpenVZ etc..
If you are looking for SSD based services, then I assume you can check kvchosting.net.
If you are looking for KVM or OpenVZ - then have a look at rockhoster.com.
If you are starting your business in the United States, then you can have a look at: hostingsource.com. If you need the one in Europe: qhoster.com will be really good option.
I suggest Hostwinds as experienced host that is providing ssd hosting with high uptime and performance. Their technical team knows how to make their servers reliable.
I can say Everest.net would meet your demands. Their hosting solutions are performing smooth and delivered with high quality service. Prices are reasonable.