Before I went on a pump (which does not use long acting insulin), I used Lantus for 12 years.
I used this because it was what I was prescribed and had no problems with it.
I have not experience of Levemir.
Hi
My personal journey. I was initially put on lantus but found whatever I did it just didn't last the supposed 24 hours. I was then put on levemir which made me realise that on lantus I didn't feel quite myself. Whilst I found levemir much more flexible for exercise etc I did always get a skin reaction to it around the injection site. Now I am on treshiba which while it covers most bases well it is not at all flexible. I am now considering returning to levemir.
I suppose like everything about type 1 it's just horses for courses because we are all so different.
Good luck with whatever you use.