Never heard of them before but it makes no sense for paying $5.99 for small transactions. The txaccelerator provided by viabtc works fine for me and it's free.
There is a service thread by one generous member here in bitcointalk forum offering free service for stuck transactions too: https://bitcointalksearch.org/topic/free-speed-up-btc-unconfirmed-transaction-to-confirmed-from-stepmike-1955028
There is a service thread by one generous member here in bitcointalk forum offering free service for stuck transactions too: https://bitcointalksearch.org/topic/free-speed-up-btc-unconfirmed-transaction-to-confirmed-from-stepmike-1955028
Free accelerators tend to have an hourly limit and there is no chance you can submit your transaction when there is a spam attack on the network or a lot of traffic sadly. I will wait to see more reviews and maybe test it If it's worth it. I know that I should pay enough miner fees in the first place but mistakes happens.
It's not worth it. Instead of paying them to edit your RBF transaction or do CPFP, do it yourself. If you do a low fee transaction, make a second transaction spending the change with double the fee that you need to be in the next block. This to miners is like 2 transactions with the correct fee, so it would be confirmed quite quickly.
You can also use a wallet that uses RBF (replace by fee), such as Electrum, so you can edit the fee after the transaction is broadcast. Both don't require a ripoff $5.99 fee, and aren't that confusing/hard to do.
