I've found the Newtones to be familiar enough, but much better.
The feel, tension, flexibility is similar, and the sound can be similar too, however I think the Newtones are a little hotter than the Sun Beams, but if you play gentle you get that round Sun Beam tone. I think they're probably more versatile as a result.
Durability wise, the Newtones are far superior, they last and last, plus any problems, they are based in the UK and are great folks to deal with.
I had SO many dud Sun Beams in packs I bought direct from the US that I just stopped using them. The QC at DR took a real turn for the worst a while back, but in a way I'm glad as I might not have ended up with Newtones
I wholeheartedly recommend you give them a go.
Eude