1) Unless you put them on moderated status, comments apparently can never be deleted (normally not a problem but I detest spam comments). Therefore, I have changed this to moderated comments, but no fear, as long as you aren't a spammer, I will put you through.
2) Space on blogger is free, and recently (like months or a year) I haven't had problems with space or pictures like I first had.
1) You can at any time delete comments, but it will show you deleted them if they already went through unmoderated, which I find a minor inconvenience compared to blogger number 1.
2) No longer a way to measure how you are using the space you have bought. Ugh. Plus they keep your bandwidth (not a problem for me I don't think) a surprise until they want to charge you more.