Let's start with the worst bitcoin wallets that beginners should avoid like the plague:

blockchain.info - comes up in search results so beginners use it but is terrible at estimating fees. There are more complaints about stuck transactions with this wallet than any other. Do not use!

Multibit HD - very buggy and many complaints by users. Again, do not use!

Because of the fee estimation problem it is important to use a wallet that lets you send a transaction replaceable or RBF. When sending from Electrum if you check the box marked replaceable and your transaction is taking too long to confirm you just click on the transaction and bump the fee up. No stuck transactions!

GreenAddress also supports RBF but is more complicated to use than Electrum, and Mycelium does not support RBF at all.

Electrum is stable, well supported and easy to use on desktop or Android and has the all important RBF ability. Start with the best is my opinion.