I currently have a gas stove, but I'm not very happy with the oven's performance due to hot/cold spots and seemingly long warm-up times.

Dad and I are in the process of renovating my kitchen, to include new cabinets we're building in his woodshop.  Thus, I can do pretty much anything I want with it and I've been thinking about having a gas cooktop and built-in electric oven mounted one over top of the other, rather than using a stove.

Is it worth it to have the two seperate, or should I go for a dual-fuel stove?

Is an electric oven that much better than a gas one?

Kharn

I just replaced mine. I just got it delivered yesterday. Don't know if it solves the problem, but I got the convection fan in mine. Supposed to help that problem out.
The dual fuel ones are a bit on the pricey side. It looked like they were about 2 times the price of a single fuel one, but it may just be where I was looking.
I don't know who makes the best, but we picked up a kenmore. Normally about 1000, on sale with some good discounts for around 800. It had pretty go reviews. Ranked as well as some professional models.

I love gas. I hated electrics, but that is just me. Since ours is a stand alone that is what we picked. I guess if I were renovating, I would contimplate the top and an oven somewhere else. Would be nice to have the extra storage.
Either way I think the convection type should cure your bad experience with gas. I guess the other question is what stove was it. Builder grade, does not compare with a regular consumer grade stove either.

For resale and just convenience get a gas cooktop and electric double oven preferably with convection in 1 of the 2.

The kitchen's only 10x10, so a double oven is out due to lack of space; we're looking at mounting the oven unit in the base cabinet, directly below the gas cooktop.

Kharn

In a 10 x 10 kitchen it may or may not fit, but if you are against it
If you go with separates you cannot use a downdraft unit as the oven will be in the way
The plus side of separates is you can repair them independently
the cost will probably be close to the same regardless dooing dual fuel vs separates
if you do get a combo unit just get the drop in with the buttons on the front  and a continuous kick vs the old slide in style with the big panel in the back
that way the backsplash is mostly visible9you lose the drawer over the slide in but the styling is well worth is
BTW  the single oven does not have to go under the cooktop

Single point of failure kind of thing, get the gas.

Quoted: In a 10 x 10 kitchen it may or may not fit, but if you are against it If you go with separates you cannot use a downdraft unit as the oven will be in the way The plus side of separates is you can repair them independently the cost will probably be close to the same regardless dooing dual fuel vs separates if you do get a combo unit just get the drop in with the buttons on the front  and a continuous kick vs the old slide in style with the big panel in the back that way the backsplash is mostly visible9you lose the drawer over the slide in but the styling is well worth is BTW  the single oven does not have to go under the cooktop

I've already got an over-the-stove microwave due to a family friend remodelling their kitchen, so thats a freebie and I dont need the down-draft cooktop (but I'll either need to order a replacement body/faceplate or get a new one in a few years, its white and I'm doing black appliances).  

I really like the continous grate designs, since I brew my own beer and I hate balancing a giant pot on just one burner's grate, which doesnt seem normal with the down-draft ones.

A tile backsplash is part of the plan, so the buttons on the front or side of the cooktop is a must. For some reason my current stove (Frigidaire, no model number that I can find) has the burner knobs on the front, but the oven controls on the backsplash. Its also gas oven/cooktop, so I'm used to not having the bottom storage, my parents have a built-in wall oven, but its at countertop height, not buried in a base cabinet.

We've already designed the base cabinets for the rest of the kitchen, this has been a rather late change. Under the cooktop is the only place the oven can go due to the dishwasher and sink locations, and the massive redesign of the cabinets putting it on the other wall would require (we can only make a 15" wide raised panel door due to the width of Dad's planer).

Kharn