For software on a PC or Mac, you should look at Vinyl Studio. It takes a little getting used to, but the tutorials are quite good. It allows you to record, split into tracks (including looking up album information and track timings), cleanup (hum and hiss removal, click removal, repair of bad flaws), normalization and outputting to various formats. The trial version is free and the cost is only $29 - a real steal. As I said, it takes a little getting used to, as do all programs, but the results can be outstanding. I would definitely give it a try. I am up to about 200 albums using it. I can easily do 5 or more albums in a day with VS, assuming the records are relatively clean.
If you are getting significantly different results with 3 different computers, you need to look at the process you are using and what else is running on the computer. The output of the PC Audio is a digital bitstream which should be handled very well by most computers. The output of the PC should be to an asynchronous DAC. What DAC are you using? And what protocol are you using - WASAPI, Asio, DIrect Sound? For player software, JRIver Media Center is a good option. Before buying a dedicated system, I would try to figure out why you are hearing such different sounds on 3 systems. A well set up PC should not have that problem. There can be differences, but they should not be as dramatic as you seem to indicate.
If you are getting significantly different results with 3 different computers, you need to look at the process you are using and what else is running on the computer. The output of the PC Audio is a digital bitstream which should be handled very well by most computers. The output of the PC should be to an asynchronous DAC. What DAC are you using? And what protocol are you using - WASAPI, Asio, DIrect Sound? For player software, JRIver Media Center is a good option. Before buying a dedicated system, I would try to figure out why you are hearing such different sounds on 3 systems. A well set up PC should not have that problem. There can be differences, but they should not be as dramatic as you seem to indicate.