After many years of knitting I finally decided to invest in an interchange needle set. I chose Lykke because I really liked the one circular needle I already owned. I am using them constantly and am now looking into buying more cords. I prefer wood, and these are very smooth and light weight. I did manage to brake one and they sent me a free replacement within the week. 
Dyakcraft changed the way they sell some of their sets so that you can customize with the needle sizes you want. If you order 8 sets of tips (any sizes), they give give you 3 cords and a case and 4 stops. If you buy individual tips, you have to buy all of the other pieces separately. So if you want a full set, it’s less expensive to choose 8 tip sizes you want and have them throw in the rest.
By the way, Dyakcraft’s customer service is excellent as is their warranty. They are also very responsive if you need to contact them. A few years ago they had some delivery issues due to a number of circumstances - a fire at their wood supplier and issues related to the development of their metal line. I was a pretty harsh critic at the time, but they’ve really come back strong. They stopped taking mass pre-orders and now sell only what is in stock on the site. I’m super impressed at their persistence coming out of a bad situation due to that supplier fire.
Juliejoolzhjoolzie - If my hubby tightens them, I don’t have any trouble. When I tighten them, I usually only have trouble with the shorter length cables.
I’m finding that I’m using my Lykke set more often than my Chiaogoos lately. I really like them!
My first set of interchangeables was from KnitPicks, and I I have knitted many a project using them. However I decided I wanted to try Chiaogoos because I heard such great things about them, and so I splurged and got the 13 needle interchangeables set. I definitely love the cables MUCH MORE than the Knit Picks cables. They really do relax. The Knit Picks are far better than the circulars at the local craft stores though…those cables may as well be wire springs! I chuckled with the “tools” that came to tighten the Chiaogoos cables to the needles - T pins! Whatever works, right? I have yet to try threading a life line using the special hole, and on my next lace project forthcoming, am eager to try that. 
I have used the lifeline hole in the past with socks.
Works wonderfully when you are in a competition and must knit a certain length - and that would some really long feet. Lol
I’m also a fan of the Chicagoo interchangeable needles. The size 2 thru 15 is great! You can purchase the sets and extra accessories on Amazon.
@knitter131 I have ordered extra needle tips for doing sleeves so that I can do them on 2 circulars. I really like that the case the set comes in will hold those extras!
@Duellingneedles I, like you, have multiple sets of my favorite sized tips but I often have them in another WIP and don’t want to remove them.
If I want to use 2 circs for a sleeve and my spare tips are busy or I don’t happen to have extras, I create 2 circs each with one tip of the correct size and a different tip of a smaller size. As long as I am careful to put the needles in the sleeve (or whatever) so I always create stitches on the tip of the correct size, my knitting doesn’t mind at all.
Yes! I’m doing this now for a blanket. I know I probably don’t need an extra set of #3 tips, so I’m using #2s on the other end.
I have tried just about every interchangeable out there. Dyak, Addi, knitpro? The ones I always come back to? My signatures. New or old. They are my go to and if I’m down and need a certain needle which is busy I use my old Addis (at least 2 of every size both 16 and 24”) as stitch holders or I buy a new signature. They are also what I buy for anyone I’m teaching to knit.
I love my 4" Chiaogoo Twist interchangeables in US 8 and below and then 5" Chiaogoo Twist in US 9 and above. Loove them. You’ll need to pry them out of my cold, dead hands when my time is done here.
I have hiha hiya sharps also, I really love them… but I knit a lot of lace! My favorite thing about them is the lifeline hole in the cable. Very easy to add lifelines with this.
I just got a set of the Chiaogoo bamboo needles and like them even more than the Lykke that I have been using. They are pointier AND they work with my red Chiaogoo cables which gives them lots of bonus points! Now I’m thinking I might sell my Lykke indigo needle set and use the money to invest in more red Chiaogoo cables!
I like the Chiagoo needles but I find that I have worn the tips down and some of them are now dull. I also like the Karbonz. Those might be my favorite. I did notice after my last project that the Karbonz now have a green wood look to them instead of being all black. I thought whatever they were made out of was all black throughout but apparently not.
I imagine that could be a problem with wood needles.
I have a set of Hiya Hiya sharps as well. I have damaged my hands with them … well fingers… they are always getting poked with those tips. 
I agree! I wish chiagoo were easier to read…they should think of making the sizing print darker or more impressed into the metal or larger OR something…