Both sleep systems and seperates are versatile , it's whatever you find best. I far prefer a sleep system ,I find it more comfortable and plenty warm enough. I use the 5 season Nash one, and have a chub bedchair cover for the depths of winter . My SS gives me everything I need for 12 months if the year ,just as a bed and bag seperate setup will if you have the right bag(s).

Just to prove we are all different I HATED my Nash SS

in theory it sounded wonderful and I could not wait to get one but the reality was quite different
its never in a million years gonna be as good as a separate bag and bed IMHO I have had lots of beds and bags before and since all brilliant

Please remember OPINIONS ARE LIKE BUMHOLES WE ALL HAVE ONE

Has anyone else found the Solar SP c-tech memory foam sleep system to be cold too? I feel the cold nowadays and it went to about 4-5 degrees I think and I was cold with both layers on. I think my trakker 365 is warmer than the Solar bag.