I'm sure I don't trust any of them and basically don't want to vote for any of them. I would love to confidently vote conservative or lib dem but there are issues with both.
Brexit:
Labour: "any deal is better than no deal" is the negotiating stance of a moron.
Lib Dem: "if you give us a bad enough deal we'll give you a second referendum and you'll win" is the negotiating stance of an idiot or a cynic.
Conservative: "no deal is better than one I don't like" is the kind of stance anyone with a functioning mind expresses before negotiating/haggling, even if really "no deal" is not an option.
I'm sure May's negotiating position on Brexit is the best of the 3 on offer.
So May normal, Corbyn terrible, Lib Dem worse.
Budgetary concerns about manifesto:
Going by what the IFS has said, none of them are fantastic. Lib Dems may be alright, but their job is to promise stuff they never intend to do, so anything that seems good in there may get Clegg'd if they get near power.
Conservative and Labour both look expensive. The main financial difference between them seems to be that Labour does not (going by the public spending increases and their rhetoric) intend to address the deficit any further, they are just going to increase it and say they're doing the opposite.
So Tory bad, Labour worse, Lib Dem impossible to tell (and they'd be in coalition anyway so none of it will happen).
Internal Security/rights:
May is somewhere between strong, and the (unacceptable) status quo on this one. Some terrifying police state stuff, I will find it hard to swallow on this one - but on the other hand she may actually deal with problems. Who knows if that's lip service though.
Corbyn thought DA would do bang up job of internal security and upholding rights, and he has a history of having links with/speaking up for terrorists while they were killing Britons.
Farron is basically meaningless on this as in everything else and can promise/criticize whatever he likes. It's right to express concerns about going too far on civil liberties/democracy, but I think if he really respected democracy and freedom as vital principles he would have been more graceful about (and less cynical about trying to reverse) the recent referendum result.
May terrible with possible very good points, Corbyn worse than that, Lib Dems irrelevant and hypocritical mosquito noise on sidelines.
Foreign relations:
May (and Boris) bad, Corbyn diabolical, Farron meaningless.
Also presumably we are going to spend unannounced billions decommissioning trident, sack thousands of people in Scotland, and have no deterrent if Corbyn gets in and instantly makes it all worthless.
...and so on
Overall, conservative seems slightly less horrendously shit than the other options. Slighly.