Been using Varifocals for several years. Couldn't go back to single vision now. I have a Specsavers branch nearby, as well as Boots, and several independants. Have used Boots and independents and Specsavers. Am currently happy with SS but admittedlly not everyone likes them...I believe they're a franchise run operation so it perhaps depends on the individual management. I'm very happy with them.
Lots of things to think about though. I find S.Savers useful because if you get a pair of specs that you don't get on with they give you a month to change your mind and will exchange for something else or refund...and in my case they stuck to their promise and did refund £40 when I changed from one type of lens to another. They adjust or clean or repair specs during ownership....so I'm pretty happy with them.
They give you a "voucher" for 50% off an additional pair of glasses within 6 months and it sounds like a waste of time, mickey mouse type voucher BUT it does actually work well and you do get any additional specs half price. (ie reading glasses or computer glasses). Varifocals are OK but you MIGHT find you still want reading glasses made up due to the fact that the reading part of varifocals is, of course, limited and it's more relaxing to read with prescription readers. Ditto the computer.
Of course, with the prices of these things they make a huge profit on the actual hardware and they must pay very little for the actual materials...hence they can afford to replace/exchange/ repair stuff at little cost to them - but they have a lot of overheads of course and there's always plenty of staff in my local branch and you don't ned appointments for most stuff (eyesight tests excepted).
I usually use their ELITE varifocal but this time went for the top of the range Tailor Made type. I didn't find the Tailor Made to be any better than ELITE so they refunded the extra money I paid for them....I actually used the refund to buy a pair of (intermediate) single vision glasses for the computer. In the case of the computer specs they made a pair up but I found it needed to be a slightly less strong prescription so they immediately took them back and made up some weaker ones...no problem and no suggestion of any additional money required.
But you do need to allow time to get used to them...without doubt your brain does adjust to them...despite initial uncertainties that you WILL have when you first use them. And they're not cheap! The other thing you might consider is whether to have Transition/Reaction/Photochromic lenses that go light and dark depending on the ultra violet light. The alternative to them is Polaroid lenses and each have their advantages. I have both types now myself but only you will know which, if any, is best for you....and you didn't ask about them anyway
but ask further if you need to know about them.
Another alternative is Bifocals but they don't have an 'Intermediate' section so your optician will likely advise if they're any good for you.
If you need to know more....ask away