Uhm, I'm really sick of Myspace in general, but I'm just biased against it because a lot of bad shit has come from its creation. I use Wordpress, which is okay, but it's certainly not fantastic. What pissed me off the most is that after only about 3 months of operation, it told me I had used up all my bandwidth for uploading pictures, and the only way to get more was to delete some! You can't even buy more space, which I was completely willing to do had it been an option! It also has a lot of issues with formating.... It loves to play around with the spacing of paragraphs, and sometimes skips all over the page as you try to type so you end up with your concluding sentence in the middle of your post. Argh!
I've never tried the other platforms so I really can't make any accurate comparisons. I do suggest you upload your photos on a seperate server regardless, to save space and all. Flickr = amazing, way more space for high res pictures than Photobucket, which I had also tried in the past.
I don't know what else to tell you other than good luck! Just try things out and have fun with it, who cares if you screw up when you're starting out? It'll get that akward bit out of the way and you'll have nothing to worry about for future blogging. Oh, and don't forget: You can always change platforms if you really hate what you chose.