Who have you used and were they good or crap? 

Anyone?

You talking for little nick nack things around the house like microwave fridge stove or bigger things ?

My realtor provided me with a year-long warranty when I bought my house, and it was with 2-10 Warranty.  He paid a bit extra to get us the $75 deductible.  I used it 4 times in the first year I bought my house, probably saving myself over $1000.  In one case, we had a small leak with our washing machine.  The technician determined it was from a crack in the detergent tray.  A replacement part wasn't available, so 2-10 offered me a new washing machine or a check for $500 to replace the machine.  I took the check for $500 and caulked the crack.  We still get about a teaspoon of water on the floor with each load, but it otherwise works fine.

I didn't renew it after the first year just because I think long term they are a bad investment, and I'm pretty handy with fixing non-major issues around the house.  But, if you want one, I had no problems with 2-10.

Mine was written in a way to guarantee it didn't cover any problem you might have.  I believe it was an American Homeshield Warranty.  Had a faucet leak about a week after I bought the house, Nope we don't cover that.

I think most of them are crooks, read what they are offering carefully.

The kind that covers your HVAC and shit.

Short version of a very frustrating story.

Home Warranty of America(provided with purchase of my house)
A/C broke(in August) on a Friday, filed claim, tech arrived Monday(paid $75 deductible)
Said Compressor was shot, and they’ll begin the process for HWA to purchase a new one for us.
Took HWA 5 business days to order the replacement.
Tech arrived 2 weeks after it first broke, with the new replacement.
They waited 2 weeks for my “special” compressor, which was the wrong one. I had to explain to the A/C Tech that I had a 410 system, and not a R22 system.
If I hadn’t been watching the work, they would have installed it.
Another week later, they had the right one installed, and refunded my out of pocket, minus the Freon.
I must have chewed every single persons ass with HWA, half the time doing their job for them just to speed up the process.
I will not be renewing.

TDLR: Home warranty saved me $1,299 on a new A/C compressor, I only ended up having to pay for the Freon. BUT, my family and I went 3 summer weeks in LA without A/C

I got a couple of buddies who are various contractors who hate home warranties.  They have to fight with them.  
I was advised against them.

On the other hand my wife uses American Home Shield on our house.  We have used them several times.  I have had really good luck.  My buddies have never been involved with AHS, so you be the judge.

AHS has worked well for me.  

I've had them a few times included in a home purchase. They were not worth what we paid for them which was nothing.
Horrible to work with. Save yourself the $ and the headaches.
ETA: my worst experience was with the company listed directly above. Made me pay for parts to bring the water heater to code which was six small pieces of black mild steel pipe that I could have bought at Home Depot for $4. They charged me close to $300 for those and another $300 for Earthquake straps that I could have bought elsewhere for $30. This was after fighting with them for 3 months to replace the defective units in the first place.
They lock you in with a specific contractor and then pull this type of shit to cover the cost of the repair. In my case I ended up paying over half the replacement cost of a covered item.
As another poster mentioned, good contractors hate dealing with them because they also do everything they can to screw them as well AND they get to be on the front lines of dealing with a pissed off homeowner.
I hate the bastards with a passion.

They are crap and I have one, the seller bought it as a part of our closing (my agent wrote it into the offer).

When I lived in the 'burbs, I used American Home Shield....They came out to fix an oven..No issue.

When I moved to the boonies, I again used AHS and my dryer broke.  The repairman in the area didn't want to come out, and instead said he would send me the part and talk me through the repair.  

I have Landmark as I have a house with original furnace and air from 1994 on my 2 story roof.  23 yr old Furnace and air con.  If it goes, they replace or repair.  I dont have any of my appliances on it.

my house came with one.
i let it expire, when i needed the ac fixed and the bill was going to be more than paying for renewing the warranty i renewed the warranty got a few other things fixed and let it expire again.

I think i'm still covered on structure.

I have purchased several rent properties and the AHS warranty was provided with the purchase. Very frustrating dealing with the bullshit but in the end saved me some money. I did not renew after the first year. I had a fairly major A/C issue that was clearly covered in the policy that they tried their hardest to not cover. Finally my realtor stepped in and said they would no longer sale their product if they didn't take care of the issue. Another was a hot water heater that left my tenant without hot water for 8 days while they made 5 service calls between plumbers, electricians and more plumbers. They kept wanting $60-65.00 call out fees for each of them. First plumber got a call out fee but said it was an electrical issue. Electrician got a call out fee but proved it wasn't an electrical issue. Then the plumbers came back and changed out heating elements one at a time and then the entire water heater. I fought them hard and got the $65.00 fee back for the electrician. Sad thing is they weren't going to send the plumber out the third time because I told them I wasn't paying again for the same service.