I have no experience with customer service as I have not had any problems.
I own two premiers, 6-18x50 and 4-12x40. The latter I bought locally this year for $130
Both are quality scopes, a huge upgrade over most inexpensive scope I have handled.
The AO on the 6-18 is smooth and fast. The magnification runs smooth and has no apparent change in POI.
As an aside, for anyone aware of the awesome destructive capabilities of spring piston airguns, the 6-18 was on my Beeman R1 springer many hundreds of pellets before being moved to my centerfire rifles. I would definitely buy another Swift, even used. The over-the-counter lifetime guarantee and fully multi-coated optics are tremendous for the money.
I use the 6-18 when shooting for tiny groups as I like the magnification. It was mounted on the following rifles for these groups

6.5x55, 3 shots in .33" at 100 yds.

17hmr, 3 in 13/32" at 100 yds.

.308 rem 788; 10 rounds in a little over an inch at 100yds.

My (then) 10 year old son, 17hmr, 5 in .69 at 100yds.
How many scopes in this price range would you feel comfortable moving back and forth between rifles, rezeroing, and shooting groups like this?
No paid endorsement, just a happy owner.
Todd