Hi, I haven't heard them side by side, but I did have a Lone Star Classic 50 watt 1x12 combo for a while and have the TC-50 1x 12 combo now.
My two clean tones for reference are old Fender Twins and the Heartbreaker (Turner Modded). I have had a Heartbreakers
since they were introduced.
Now these are just my opinions, and keep in mind I use a Les Paul most of the time and that makes a big difference.
I found the LSC to have a very pristine, icy clean. It seemed kind of "clinical" to me, with an emphasis on the high end that I couldn't dial out.
Nothing wrong with it, in fact i could see it being EXACTLY what a lot of people want, it was just not my favorite.
I love everything about the TC-50. The cleans are more like the Heartbreaker or a Twin, but it is more flexible. It has more of that high presence,
unlike the Heartbreaker, but it goes from that later silver face clean to thicker, warmer jazz type clean with a move of the kids knob.
The amp overall to me is like a Heartbreaker that is more mid-focused instead of low focused, or a Lone Star that is more mid focused and less high
focused. Although, you can dial it as high or as low as the other two.
Now, and this is very subjective, when I put 6L6's in it, the cleans jumped up to even more beautiful. However, and I only have done it once so far, I
did feel like live with a band the subtle loss of something in the high mids seriously impacted my ability to sit audibly in the mix (the Heartbreaker suffers from this also).
I am so infatuated with the TC that after playing about 20 gigs with it that i have ordered a custom covered head so I can use it with various cab configurations.
YMMV