A couple months or so ago, I was accidentally sent a roll of Fujifilm Velvia. It's a film stock I've never used before so rather than send it back. I thought I'd give it a go on a visit to Folkestone harbour. It uses E-6 processing so you have to send off the film, and thus had be languishing undeveloped for quite a while. No Boots 1-hour developing this time! Slide film differs from colour negative because it produces positive colour image instead. Which is great because you can see how many terrible pictures you took, without having to make contact sheets, get prints or scan in every picture. It requires a more expensive processing method and so you can't get it developed on the local high street. I finally sent it off and got to see the effect for myself. It's slightly magical, I have to admit!
However, there's a basic reason I don't use this film. It might be obvious from these contacts. Velvia is notoriously tricky to expose correctly, especially for the reckless amateur such as myself. For 35mm, I use only pre-1980 cameras and most of those either have unreliable light meters, have broken light meters, don't have batteries or don't have a light meter full stop. I use 400 ISO negative film mostly because the exposure latitude is so great that I can get anyway with over and under exposure when I do my guesstimations based on the 'Sunny 16' rule. I can deal with slight underexposure, but blown out highlights are awful as they contain no information which can be retrieved in post. In this case, I overexposed even with the light meter set at the correct ASA rating. In future, I'd change the speed to compensate, but I use quite a few 35mm film cameras. Experimenting to find the correct solution for all of them would take a lot of time and money. I'd rather just have the shot...
Velvia is something I'd save for my Medium Format system which has a relatively decent light meter, and the larger slide image makes full use of the film's qualities. When exposure is spot-on you get super-duper saturated colours and an almost grain-free image with a ton of detail. A lot of professional landscape photographers continue to use Velvia because these qualities outweigh the advantages of digital.
I think unless you're serious and careful about making sure you get a correct exposure, it's safer to stick to colour negative because of the wider exposure latitude. I'd personally recommend Kodak Portra for the connoisseur, or in a pinch (and only on a sunny day) Kodak Ultramax which can be bought from Boots. Kodak Ektar is also great, but is similarly finickity with correct exposure. The other choice is a decent hand-held meter and do it the old fashioned way!